Author Bob Woodward and his publisher, Simon and Schuster, announced yesterday that they have filed a $500,000 suit against a Beverly Hills doctor who alleged he was libeled in Woodward's best seller "Wired: The Short Life and Fast Times of John Belushi." Dr. Robert Feder filed a $20 million lawsuit in Los Angeles in December against Woodward and his publisher, contending the book contained false statements.

Woodward, in filing his first lawsuit in 14 years as a journalist, charged Feder with abusing the process of the court. He said, "We can demonstrate that Feder knowingly instituted and maintained a frivolous libel action against me and my publisher." Woodward, a Washington Post assistant managing editor, explained that when informed that Feder had been considering action against him, he took the "extraordinary step of arranging for Feder and his attorneys to review my research materials and interview notes relating to him . . ." After three months, Feder filed his libel action.

Feder's attorney, Allan Browne, said yesterday he had not seen the suit. "His [Woodward's] cross complaint is no more than a smoke screen and a diversionary tactic which most defendants who are guilty engage in under the theory that the best defense is a good offense."