Vladimir Bukosky, 34, a dissident activist who was relased from a Soviet prison just two months ago, yesterday told a congressional commission that the United States should constantly press the Soviet Union to respect human rights.

"The fate of the world depends on the conduct of the Western nations at this time of growing crisis," Bukovsky said. "A firm, relentless and constant stand by the West will force the Soviet Union to recognize political realities."

Bukovsky appeared before the Commission on Security and Cooperation in Europe, which is responsible for investigating implementation of the Helsinki agreement on European security signed in 1974. A bipartisan group of senators and House members belong to the commission and heard Bukovsky's testimony.

One of them, Sen. Richard (Dick) Stone (D-Fa), asked Bukovsky what he meant by " political realities" that the soviets would have to face. Other commission members pressed Bukovsky similarly.

"If the Soviet leaders are convinced that the protests against persecution (of dissidents) in the U.S.S.R. are not merely a temporary expedient," Bukovsky said in reply to one question, "but will lead to a consistent, steadfast Western policy, they will have no choice but to recognize this and take it into account in their relations with the West."

Bukovsky attributed the failure of past pressure on the Soviets to its inconsistency. For example, he called the Jackson Amendment - which tied U.S. trade benefits to the Soviets to increased emigration of Jews from the U.S.S.R. - a "tremendous moral victory for the United States."

Several members of the commission noted that after the Soviets in effect rejected the Jackson Amendment and renounced the Soviet-American trade agreement, the rate of Jewish emigration declined - from an annual rate of more than 30,000 in 1973 to just over 10,000 today, according to Rep. Millicent H. Fenwick (R-N.J.).

The reason the Jackson amendment failed to achieve greater Jewish emigration, Bukovsky suggested, was that other Western countries did not adopt a similar policy, and the Soviet assumed that the United States would soon drop it.

Bukovsky declined to tell the commission that direct pressure from the West would force the Soviets to do or not do certain things. Instead, he repeatedly said that consistent Western pressure would compel the Soviets to "take account of" what he called "new political realities."

Bukovsky said the USSR has no intention of fulfilling the human rights provisions of the Helsinki accord, and only Western pressure can change its attitude.