After six months as a U.S. senator, the word most often used to describe John W. Warner's performance is "surprising."

What the Virginia senator hasn't done is about as surprising as what he has, according to Capitol Hill observers. They say he hasn't become a regular on the party circuit with his actress wife, Elizabeth Taylor. Nor has he been the showboat that angered critics during the campaign. He hasn't done a lot of dumb things.

What he has done, those observers report, is keep his nose to the grindstone, pays tribute to his legislative elders and take a bipartisan interest in state and regional affairs.

"He's reaching out to the citizens more than we've exprienced before," said Judy Goldberg, Common Cause's Virginia executive director.

Senator Charles McCMathias, the liberal Maryland Republican, said Warner is "doing his homework." He said Warner already has accomplished something some senators never do. "He's been accepted, he's a member of the club," Mathias said.

Not all of Warner's colleagues are that enthusiastic. Another senator scoffs that "anyone would be better than Scott," a disparaging reference to William L. Scott, Warner's predecessor.

There have been flashes of the arm-flailing and ego-tripping that marked much of Warner's campaign last fall.

Warner attempted to take credit for a Metro financing bill that Mathias had actually drafted. The new senator and his staff quickly apologized after a minimum of mumbling about a misunderstanding.

And there have been examples of glitter-without-substance, as exemplified by a camera-laden subway trip to Rosslyn for a meeting with regional officials on Metro financing, which was followed by a quiet chaffeured drive back to the Capitol.

But Senator Harry F. Byrd Jr., Virginia's senior senator, said he and Warner are already closer than he ever was with the three other Virginians with whom he has served in the senate.

Warner solidified their relations with his first legislative action - cosponsoring Byrd's resolution that critized the Carter administration's Taiwan policy.

One senator, observing Warner frequently chatting with Byrd on the floor, said Warner "cultivates him (Byrd) without fawning over him or being deferential. It's made a difference in Harry's attitude."

Warner, 52, a handsome, grey-haired lawyer, was an unknown quantity when his term began January 2. He had no legislative experience. He had been elected by the razor-thin margin of 4,721 votes our of 1.2 million cast defeating Andrew P. Miller, a Democrat with lackluster campaigning techniques. And he got the Republican nomination only because the party's first choice, Richard Obenshain, was killed in a plane crash while campaigning.

Warner's baggage was heavy.

He came to public notice courtesy of Richard Nixon, as a Secretary of the Navy.

He got his estimated $7 million fortune in the breakup of his first marriage, to the daughter of multimillionaire Paul Mellon. His lavish spending in pursuing the Senate seat, including sizable personal loans to his campaign, became an election issue.

He was known derisively during the campaign as Mr. Elizabeth Taylor, the actress' seventh husband.

He was a pushover for the cartoonists. "Doonsbury" creator Garry Trudeau was so vicious is his attacks - describing Warner in one strip as "some dim dilettante who managed to buy, marry and luck his way into the senate" - that some papers in Virginia and elsewhere refused to run the strip. In a Washington Star editorial cartoon titled "The Virginia Hunt," Pat Oliphant showed Warner, the gentleman farmer, riding Taylor, the thoroughbred, to victory.

But those early assessments began to change. The Economist, a British magazine, rated Warner's early performance that of "a serious student of the issues, reminiscent, ironically, of William Spong, the thoughtful and moderate Democratic senator who was upset six years ago by Mr. Scott (Warner's predecessor).

His wife, who is vacationing in Florida, said in a telephone interview that people are beginning to think of her "more as Mrs. John Warner and less as Elizabeth Taylor," which pleases her. She attributes the change to John's contagious snese of enthusiasm,"

She is anxious to be "considered no different than any other freshman senator's wife," as impossible as that may be. She said she hasn't worked professionally since Warner's election and therefore has had time to entertain at the traditional dinner parties in their Georgetown home and do the volunteer work, including bandage rolling; that is traditional for Senate's spouses.

Asked if she had difficulty adjusting to Warner's moderate-to-conservative views after a lifetime of being perceived as politically liberal, said "I've never been a people person. "I've never been a partisan."

She said she and her husband don't agree on every issue but that they discuss issues, never argue about them. And he is the senator.

In another surprise to some, the Warner's have maintained a low profile on the party circuit. "I've never been one for parties," Taylor said. She added that because Warner works so hard and so long, "when he's at home, he needs to rest and relax, when he's not doing his homework. You can't successfully combine that kind of a schedule with partying."

The senator quipped that "with the shah gone, the parties aren't the same anyway." (The Warners were star attractions at the lavish affairs hosted by now-deposed ambassador Ardeshir Zahedi at the Iranian Embassy.)

Former Governor A. Linwood Hotlon, who finished behind Obenshin and Warner at last summer's GOP nominating convention, believes Warner is off to a good start. "He want to solve problems," Holton said, "and he's not hung up about real or imagined ideological differences."

Early on, Warner met with all 10 Virginia members of the House, regardless of political bent, and discussed possible cooperation in the interst of the Old Dominion.

His decision to walk across Capitol Hill and confer first with Representative Herbert E. Harris II, the liberal Democrat from Northern Virginia, raised some eyebrows. A Republican in the state house in Richmond said the "odd couple" alliance alienated some staunch conservatives.

But Holton defended the overture, saying Warner "ought to work with whomever the people elected" on mutual concerns.

There are three things you learn not to do when you attend as many receptions as a senator does, Warner explained as he bounded up the steps of the Cannon House Office Building toward a cocktail party given by an organization of truck stop operators.

"You don't drink, don't eat and don't linger," said Warner, who followed his own device in attending three similar receptions in 90 minutes on a recent Wednsday evening.

On the other hand, he explained you do: sign the register or pick up your name tag "so the next day they'll know you showed up"; find the person who knows what his organization wants from Congress, and a pose for a picture that possibly will appear in the group's in-house, national publication.

"Most of these people are here in Washington for a good time and haven't any idea what their legislative goals are," said Warner, as he pumped hands, waved off the inevitably offering of drinks and repeatedly agreed that yes, he also was sorry that his wife couldn't make it.

As United Air Lines flight 328 touched down at Byrd Field in Richmond, Warner put away a stack of issues papers on the SALT II treaty glanced at his schedule for the rest of the day - a luncheon speech, several private meetings, a colleague commencement and a patio party - and proclaimed: "Politics - I love it."

Judy Peachee, his Richmond representative and office manager, scolded him for stopping at the counter inside the terminal to buy cigars, pointing out that he was already half an hour late for the luncheon. On the drive to the John Marshall Hotel, Peachee briefs her boss about the interests of the 125 people who had forked over $9.06 each for the no-host, Dutch-treat affair, which the senator's staff had arranged.

Warner told Peachee he planned to give the audience a look at a typical day in the life of a senator, using the previous day's schedule as the example. Peachee insisted the crowd would rather hear details and his views on SALT II, on which he remains uncomitted. But Warner, a bit testy, said Judy, let me do it my way for a change."

Which of course he did. And they loved it.

It hasn't taken Warner long to figture out that no matter how sophisticated or well informed, most listeners are easily captivated by an inside glimpse at life in the nation's captial.

After the luncheon, which was largely question-and-answer stuff, Warner returned to the Federal Building, the same eighth floor suite once occupied by Scott.

In the main office, there are only two pictures on the wall. One is Warner with Obenshain, the other Obenshain alone, a silent tribute to the highly respected conservative who beat Warner fair-and-square last summer in a four-way fight for the nomination at the Richmond convention center, a couple of blocks away.

Peachee was Obenshain's campaign manager, so it is another tribute that Warner picked her for the important task of coordinating his area offices. Although Scott maintained only the Richmond office and Byrd has no offices outside of Washington, Warner has four district operations in Richmond, Norfolk, Alexandria and Marion all directed by Peachee.

Peachee admits that initially, she has misgivings about Warner, based on what she heard early in the campaign. "He was good on military and foreign issues, because of his service as secretary of the Navy, but he was weak on domestic issues," she said recently. "But he's better-informed now."

Warner's success - if it can be called that this early in a six-year term - results partially from simply hard work. A staff member employed by the Democratic majority on the Senate Commerce Committee said Warner, along with Chairman Daniel K. Inouye (D. Hawaii), is the hardest working, best-informed member of the subcommittee on merchant marine and tourism.

(The first piece of legislation signed into law bearing Warner's name came out of that subcommittee. On June 19, President Carter signed S-199, which empowers the Federal Martime Commission to crack down on foreign firms that bribe shippers for business Inouye was the sponsor, and Warner, the ranking minority member, was principal cosponsor.)

A senator is no better or worse than his staff, the saying goes, and Warner's staff is well regarded and a factor in his good early showing.

His administrative assistant, Albert A. Applegatem was former Michigan Senator Robert P. Griffin's top aide. Warner's legislative assistant is John T. White, an 18-year Hill veteran and one of five holdovers from Scott's staff.

Two other top aides - Charles F. Goodspeed, who runs the Alexandria field office, and Andrew F. Walquist, who is executive assistant - worked for Warner at the American Revolution Bicentennial Commission.

Press secretary Bill Kling, a former Chicago Tribune political writer, "helps (Warner's reputation) a lot among other staffs," said a Midwestern Democrat's press secretary. Kling's assistant, Irene B. Forde, is one of three blacks and one of 19 women on the 33-person staff.

Warner's press operation is low-key another surprise considering last year's high-powered, image-conscious campaign. Kling and Forde have issued 40 press releases since Warner took office, about average for a freshman senator. By comparison, Byrd employs three press aides, who have cranked out 75 releases this year. Mathias who comes up for reelection in 1981, has two press persons, who have put out 81 releases plus a weekly column and radio tapes.

Richard Lerner, press secretary for Senator Bill Bradley (D-N.J.), another freshman said Bradley a former professional basketball star, and Warner already are well known beyond their states and "don't need the publicity."

The commencement address was at Southside Community College in Keysville, a crossroads village 90 minutes southwest of Richmond. Peachee and two other devoted Obenshain workers, Mike Thomas and Bill James, drove to Richmond to take Warner to the school.

It was a lovely June evening, and the ceremony was on the lawn, James, who teaches economics at Southside's other campus, 40 miles east in Alberta, filled Warner in on the school and its student.

Most of the 194 graduates about half of whom were black, were first generation college students and the two-year diploma marked the end of their formal education.

Warner, an engineering graduate of Washington and Lee University and law graduate of the University of Virginia, is in tune with that reality.

"Not everyone wants ot needs a four-year college education," he said, "Some of us are at our best working in the fields or forest under God's great sky, planting, harvesting, working with farm animals - enriching, tilling and moving the earth. Some of us find life's greatest satisfactions in working with our hands - working with tools and instruments - building repairing, shaping and assembling.

The campus is located next to a small airport, and two pilots were making practice landings, roaring low over the crowd, drowning out Warner's speech. Halfway through it, he gave in to the noise and the mosquitos and called it quits. He was applauded loudly.

After he left the school, after touring its workshops, Warner spotted a family trying unsuccessfully to break into their locked car.

"Give it to me," he commanded, and the wire coat hanger was dutifully given to the senator. Warner handed his jacket to an aide and deftly worked the coat hanger between the door and frame, fastened a loop around the lock and pulled it up as the onlookers cheered.

"That's what you get with a good Navy exprience," bragged the former secretary of the Navy. "How many votes do I get here?" he asked. When they answered ALL of them," Warner waved and rode off in the back seat of his escort's car the night a triumph.

Sunday morning, and Warner, wearing cowboy hat and denim jacket and trousers, tromps through the rain to pick spring onions from his garden.

"Nothing like fresh-picked fried onions to pick up a breakfast," he lectured a visitor. While frying the onions, along with potatoes, on the gas stove in his 163 year-old farmhouse at Atoka, in Fauquier County, Warner talked about his love of farming and how some critics have understandably suggested that his wealth means he is not a real farmer.

When Warner and Obenshain were vying for the GOP nomination last summer Warner recalls "Dick got a lot of mileage out of telling farm audiences that 'John Warner is the only farmer in Virginia who has a swimming pool in his barn.

Which may be true, Warner conceded with a grin. But he quickly added that there are nine other barns on the 2,000-plus acre farm. They are used for more traditional purposes, such as storing hay and corn and sheltering horses, cows, chickens and a fleet of vehicles that includes a snowplow tractors and a four-wheel-drive Jeep Wagoneer, which he drives across the pastures to check his herd.

Warner said he is lucky to spend two weekends a month at the farm. He and ETW, as he sometimes refers to his wife, live in Georgetown with Warner's 17-year-old son, John, a St. Albann's junior.

Between them John and Elizabeth Warner have seven children, all between 16 and 22 years old. Three of them are from Warner's first marriage to the former Catherine Mellow. The other four are from Taylor's six earlier marriages. One recent weekend when most of them were in the area, Warner counted 11 teenagers at the farm, most bunking on the red barn loft, from which the could jump or dive into the 14-foot deep indoor pool.

Martha Warner, the senator's 89-year-old mother, lives in a small new house on the farm, which also has residences for the four tenant families who work for Warner.

On June 22, Warner and Harris, a kindred soul when it comes to publicity, visited the Manassas Battlefield National Paro to examine legislation Harris proposed to expand the park.

Their respective secretaries announced they would travel the 28 miles to Manassas aboard a Park Service helicopter for an aerial view of the park, an action sure to attract cameras. They would then attend a public hearing called by Warner.

But shortly after a reporter inquired about the time and location of the lift-off, the senator's press secretary called the reported and said the two would be driving."

A park service spokeswoman said, however, that someone from Warner's office had canceled the request for the helicopter. "Maybe they thought it would use too much gas," she said. CAPTION: Picture 1, Sen. John Warner listens to a briefing on energy on Capitol Hill. By Frank Johnston - The Washington Post; Picture 2, Sen. John Warner talks to reporters at the end of a hearing on Capitol Hill. By Frank Johnston - The Washington Post; Picture 3, Sen. John Warner (R.Va.) eats a quick lunch while working in his office. By Frank Johnston - The Washington Post