The Central Intelligence Agency yesterday accused Frank Sneep, a former CIA analyst who has written a book critical of the U.S. evacuation from South Vietnam, of violating his secrecy oath.

The agency also said Snepp, who spent five years in the CIA's Saigon office, had violated a "specific promise" he made May 17 to CIA Director Stansfield M. Turner that he would submit his book to the agency for security clearance before publication.

Turner relayed the charges to the Justice Department yesterday, and Attorney General Griffin B. Bell said he had referred them to the Civil Division.

David Anderson, head of the division's litigating section, said he was looking into the question of whether any action could or should be taken against Snepp or Random House, which plans to publish the book, "Decent Interval," next week.

The book charges that the April, 1975, evacuation was an "institutional disgrace" caused by major intelligence failures by U.S. Officials in Washington and Vietnam.

Snepp, 34, who had been the CIA's principal analyst of North Vietnamese political affairs, resigned from the agency in December, 1975. He declined to comment yesterday on the CIA charges that he violated his oath.

However, he said in a postscript to his book that he had "resolved not to submit my manuscript to the agency for clearance and censorship" after for learning that a CIA official had briefed two journalists on the evacuation.

"In my view, if the CIA could officially leak to the press to whitewash its role in Vietnam, it had forfeited the right to censor me in the name of security or national interest," Snepp wrote.

CIA spokesman Dennis said yesterday the agency is not sure whether the government has any power to prevent publication or to sue Sneep. "All you can do is present the facts to the Justice Department and say, 'I object,' he said.

The government's legal difficulty results from the fact that Snepp's book is ready for publication and was the subject of front-page articles in yesterday's Washington Post and New York Times.

The book was written and edited in great secrecy for fear that the agency would try to enjoin the Snepp from submitting his manuscript to a publisher without clearing it first with the CIA.

In 1972 the CIA obtained a federal court injunction stopping Victor Marchetti and John D. Marks from publishing "The CIA and the Cult of Intelligence" without prior clearance.

Marchetti and Marks fought the injuction and lost, and then fought for restoration of more than 200 deletions made by the CIA when the book was published in 1974. In 1975 the Fourth U.S. Circuit Court of Appeals, reversing a lower court, upheld the government's right to suppress classified information. The Supreme Court declined to review the decision.

In another case, former CIA official Philip Agee avoided CIA censorship by publishing his book, "Inside the Company: CIA Diary," outside the country - in Londonin 1975. Earlier this year theJustice Department wrote Agee that it had closed its investigation of him and that he could return to the United States without facing prosecution for disclosing CIA secrets.

Melvin L. Wulf, A New York lawyer who handled both Marks-Marchetti and gee cases, said he thinks "there's nothing the CIA can do to suppress the Snepp book, and that's the way it should be. Once the book is in the public domain, it's a wholly different constitutional kettle of fish."

Asked about the allegations in Shepp's book, the CIA said it is investigating them. An aide to Henry A. Kissinger, secretary of state when South Vietnam fell, said the allegations were "nonsense." Graham Martin, U.S. ambassador to Sout Vietnam at the time,is now in Italy and could not be reached for comment.