His critics call him "Senator No." His voting record, they argue, is atrocious - he's always against everything. Rarely, they say, does he ever win in the U.S. Senate.

But 11 months before the 1978 elections, North Carolina Sen. Jesse A. Helms, the first Republican elected to the Senate from this state in the 20th century, is considered strong enough to get enough "yes" votes to continue as a national spokesman for conservatives.

Even Helms' opponents in the Democratic Party, which has a 3-to-1 voter registration margin, view him as the forntrunner for the November, 1978, election.

"It is going to be tough to beat him," observes Betty R. McCain, chairman of the state Democratic Party.

Helms, 56, a former television commentator long active in North Carolina politics, was elected to the Senate in 1972, helped by the Nixon landslide and deep divisions among the state's Democrats. A former Democrat, he did especially well among conservative Democrats in the eastern part of the state who had watched his nightly television editorials for more than a decade.

Recognizing the Republican Party's minority status in the state, the Helms campaign for 1978 began early, putting conservative fund-raiser Richard A. Viguerie of Falls Church, Va., to work last January.

Helped by letters from Ronald Reegan, whom he supported for the GOP nomination last year, and from Gerald R. Ford, the Helms' re-election campaign has raised $1.8 million so far. In 1976, the most expensive Senate campaigns cost about $3 million. If the Helms' campaign continues at its present pace, it should easily surpass the 1976 level of expenditures.

Viguerie's direct mail campaign has been expensive. Almost every dollar has been plowed back to raise more money. However, Helms' campaign officials say the "prospecting" has turned up more than 100,000 persons in the nation willing to give more money to Helms next year.

Helms' aides also began organizing quickly, opening a headquarters with a paid staff of about 20 persons a year ago. The senator has made regular visits to the state, often to attend banquets in his honor, bringing along such guests as former astronaut Alan B. Shepard, Sen. James B. Allen, a conservative Democrat from Alabama, and Lou Holtz, former head football coach at North Carolina State University who is now head coach at the University of Arkansas.

Some analysts say Helms has established himself among rank-and-file voters in North Carolina as a crusader, standing up for what he feels is right.

The Senate is a favorite target in Helms' campaign speeches back home - as are Communists, bloated federal budgets, welfare chiselers, liberals and bureaucrats. He emphasizes a return to "Christian principles" as the path to political salvation, and tells his listeners, regularly, "I don't care which party straightens this country out, just as long as one does."

Helms has seized the "Senator No" tag and is attempting to turn it to his advantage. At a recent speech here, before nearly 2,500 persons, he smiled and declared, "I am 'Senator No,' and I am glad to be here tonight." He then asked, "Isn't it the political yes-men - the politicians so free with other people's money - who are the worst enemies of the people?" His audience responded with cheers.

Many Democrats cringe at Helms' concentration on such intersely emotional issues as busing, federally funded abortions and the proposed Panama Canal treaties - all of which he vigorously opposes - instead of bread-and-butter issues like jobs and the economy. But they agree that Helms appears to have struck a sympathetic chord among many voters.

"He is tapping a latent fear, bewilderment, and frustration that a lot of people have. He oversimplifies, he overexaggerates, and he has a simplistic notion of what America should be like, but he does evoke an emotional response," said one political scientist who has watched Helms for years.

Helms is not expected to face any opposition in the GOP primary next May, allowing him to avoid interparty feuding.

Several Democrats are expected to seek their party's nomination, including Charlotte banker Luther H. Hodges Jr., whose late father was Secretary of Commerce in the Kennedy administration after serving as governor of North Carolina in the late 1950s; state Sen. McNeill Smith of Greensboro, a long-time crusader for civil rights; and state insurance commissioner John R. Ingram who has made the insurance industry the target of vehement attacks during his five years in office.

State Attorney General Rufus L. Edmisten, who spent 10 years in Washington as an aide to former Sen. Sam J. Ervin (D-N.C.), recently decided against running, saying he was not ready to enter a third political campaign in four years. Edmisten was viewed by many politicians as having the best chance to defeat Helms, and his decision not to run was taken as another sign that at this point in the campaign, many bettors are putting their money on Helms.