President Reagan yesterday announced he will nominate James H. Burnley IV as his new transportation secretary and praised Burnley for his "easy manner" -- despite the deputy secretary's reputation for abrasive battles with senators on aviation and rail issues.

Reagan also named Mimi Weyforth Dawson, a member of the Federal Communications Commission, to succeed Burnley as deputy. Dawson, a former administrative assistant to Sen. Bob Packwood (R-Ore.), was appointed to the commission by Reagan in 1981. Her term expires next year.

"Add to his grasp of public policy, his personal integrity and easy manner and you can understand how he earned his reputation as both a sound policymaker and excellent administrator," Reagan said of Burnley at a Rose Garden ceremony.

Burnley, 39, is expected to face a tough confirmation hearing because of his poor relationship with Congress.

The nomination was stalled for several days while White House chief of staff Howard H. Baker Jr. tried to placate Sen. Frank R. Lautenberg (D-N.J.), who felt Burnley had insulted him on a national television program last May.

Ultimately, Burnley is expected to be confirmed because his problems are tied to his personality, not his professional qualifications. As deputy secretary, Burnley was in charge of the department's day-to-day operations. He has been running the department since Elizabeth Hanford Dole resigned Oct. 1 to campaign full-time on behalf of the presidential bid of her husband, Sen. Robert J. Dole (R-Kan).

No confirmation hearing date has been set, and Sen. Wendell H. Ford (D-Ky.), chairman of the Senate Commerce aviation subcommittee, warned that "the process will be very slow if I have my way." Ford had earlier announced opposition to Burnley.

"As to Burnley, he cannot run the department if he approaches future situations as he has approached the ones in the past that I have been associated with," Ford said. "He has burned so many bridges that it would take the Army Corps of Engineers 100 years to rebuild them."

Aides to Sen. Ernest F. Hollings (D-S.C.), who, as chairman of the Commerce Committee will chair the hearings, speculated it may be three to four weeks before a hearing date is set. Hollings said at a news conference he expects the confirmation "will occur in an uneventful fashion."

Sen. Nancy Landon Kassenbaum (R-Kan.), who earlier had warned the White House that Burnley's nomination "could be a contentious one," said yesterday she hopes Burnley can be confirmed quickly. Kassenbaum had backed a Kansas businessman to become secretary, but was unable to convince Reagan to nominate him.

Sen. John C. Danforth (R-Mo.) described Burnley as "very able and highly qualified," adding that "considering there is only a little over a year left in this presidential term, Jim Burnley would be able to assume his responsibilities with no break in continuity."

Dawson, the new deputy, is the wife of Rhett B. Dawson, assistant to the president for operations. She was a legislative assistant to former Missouri Democratic representatives Richard Ichord and James Symington before joining Packwood's staff in 1973. While at the FCC, Dawson, 43, has been described as a strong proponent of the deregulatory path taken by FCC Chairman Dennis R. Patrick and former chairman Mark S. Fowler.

Burnley, as the No. 2 official at the Transportation Department, was involved in the sale of Conrail, the freight railroad created by the government from the bankrupt Penn-Central and other failed railroads, and the transfer of Washington's National and Dulles airports from federal control to a regional authority.

He helped create the department's policy for rebuilding the air traffic control work force in the wake of the 1981 controllers' strike and handled the administration's efforts to sell Amtrak.

Burnley was also involved in developing the department's policies on aviation security and safety during the months of heightened fears over international terrorism and domestic worries about near-collisions.

The most public example of Burnley's abrasive style occurred last spring, when he appeared with Lautenberg, chairman of the Appropriations transportation subcommittee, on CBS News' "Face The Nation." On that broadcast, Burnley criticized his critics -- who included Lautenberg -- as speaking "gibberish and nonsense" and scaring air travelers with "loose, quick and glib" remarks about air safety.

The broadcast took on an almost legendary reputation over the summer months as it was cited time and again by congressional staff members as the prime example of Burnley's arrogance. Then, when Burnley emerged as the leading candidate, Lautenberg told the White House he would join the opposition unless Burnley apologized. Burnley met with Lautenberg, then followed up with a letter dated Oct. 1, in which he stated he "regretted any loss in our positive working relationship."

That letter did not satisfy Lautenberg, so Burnley was asked to write a second letter, which was delivered to Lautenberg's home by courier Wednesday night.

In it, Burnley said, "To the extent that any member found my remarks to be an affront to the elected representatives of the people, I want to express my sincere regret and to apologize."

The former North Carolina trial lawyer rose to the second highest job at the Transportation Department after only six years in Washington. After Reagan's election, Burnley was named director of VISTA at a time when the administration was trying to shut down the agency.

A year later, he moved over to the Justice Department as an associate deputy attorney general. In 1983, he was appointed general counsel to the Transportation Department and moved up to the deputy's job the same year.

Burnley grew up in High Point, N.C., where he was a member of his high school's prize-winning debate team. He holds a bachelor's degree from Yale University, where he was a drum major in Yale's marching band, and a law degree from Harvard University.

He returned to North Carolina, where he practiced law and plunged into Republican politics. Between 1976 and 1979, he was party chairman of the Guilford County Republican Party and was credited with reviving the party after the Watergate-era setbacks.

News accounts then described him as a "hard-hitting political leader who enjoyed controversy and debate."

On election night in 1978, he strolled into Guilford's Democratic Party headquarters, puffing a big cigar, to gloat over several Republican victories. The Democratic chairman, outraged, threw him out.