Georgy Vladimov, a writer who was one of the rising stars of the Soviet literary establishment until he challenged censorship five years ago, has asked permission to emigrate to the West.

In a bitterly defiant letter to Soviet leader Yuri Andropov, Vladimov said he decided to "quit Russia" after continual harassment by agents of the KGB, the Soviet secret police, and threats to him and his wife.

Vladimov, 52, was interrogated for two days last week and was requested to submit by Jan. 20 a letter renouncing his "anti-Soviet" activities, naming "his contacts" and pledging not to publish abroad any of his works without formal approval by Soviet authorities.

The investigators told Vladimov that if he did not submit the requested letter, the authorities intended to press criminal charges. Vladimir said his wife, Natalia, who also was interrogated, was threatened with arrest.

Writing to Andropov, Vladimov said he had told the investigators that he had no intentions of writing such a letter.

"I assure you that neither investigation, nor trial, nor consignment to prison camp or exile will alter my convictions and will not be worse than the dishonor I should incur by the recantation you demand," Vladimov said in the letter a copy of which was obtained by The Washington Post.

He said he was prepared to leave the country for his wife's sake. "It seems," he wrote to Andropov, "that there is 'sufficient material' on her. Her main guilt is that she does not make an effort to get me to write the above mentioned letter and that she prevents me from associating with people who might influnce me 'in the right direction.' "

Reminding Andropov that he was once the KGB chief, Vladimov described KGB threats against his wife as a "contemptible action."

"I propose another way out, less detrimental to our national prestige. I am prepared to leave Russia," he wrote. "To be compelled to do this is painful and humiliating for us." He said he had offers to go to West Germany to teach and to France.

Vladimov ended the letter by asking Andropov's assistance "for my depature from the Soviet Union for a one-year period." He also requested that the KGB "leave us in peace" until departure.

Vladimov gained considerable popularity here in 1961 with the publication of his first novel "The Great Ore." His was instantly elected to the Writers Union and the book was hailed for the quality of its sociological and psychological insights about the lives of Russian blue-collar workers.

His "Three Minutes of Silence," published in 1969, increased his popularity but also classified him as a nonconformist authors. His "Faithful Ruslan," widely circulated in the manuscript form here, is regarded as a masterpiece. It has been published in the West.

Vladimov became increasingly critical of censorship and literary orthodoxy, the basic policies of the Writers Union. He quit the union in 1977 and became associated with the dissident movement by assuming the chairmanship of the Moscow chapter of Amnesty International, the London-based, human-rights monitoring organization.

Although the Moscow chapter exists only in name, Vladimov's contacts with dissidents brought him under police scrutiny. In addition some of his works, including the play "The Sixth Soldier," were published in the West.

Since the expulsion from the Soviet Union of writer Alexander Solzhenitsyn, Soviet authorities have given exit visas to a number of nonconformist writers, including such authors as Vladimir Voinovich, Viktor Nekrasov, Vasily Kuznetsov, Lev Kopelev and Vasily Aksenov. In virtually all such cases, the writers were given informal official assurances that their requests for exit visas would be granted.

There was no indications that Vladimov had received similar assurances.

Valdimov's home was subject to two KGB searches last year. During both searches, the agents confiscated books, manuscripts and other printed material.

During the latest search in December, the agents also seized the author's two typewriters. Vladimov said he had written all his works on one of them, which he bought years ago from the proceeds of the sale of a suit. He said the police also searched the apartment of his mother-in-law.