In a new move toward improved relations with the Soviet Union, President Carter's science adviser, Frank Press, will lead a delebgation of U.S. scinetists to Moscow next month for talks with their Soviet counterparts, the State Department announced yesterday.

The visit, which will take place Feb. 5-7, had been scheduled for last July, but was canceled after the administration put a freeze on most high-level official trips to the Soviet Union because of the trials of Soviet dissidents and the arrest of and American citizen in Moscow.

That moratorium was quiety ended three months later as the strains in U.S.s/oviet relations began to ease. Since then, Treasury Secretary W. Michael Blumenthal and Commerce Secretary Juanita M. Kreps have headed official missions to Moscow.

State Department officials said the rescheduling of Press' trip was due to a number of factors, including the resolution of many problems that had troubled relations between Washington and Moscow last summer.

Some sources said the timing of the Press visit also is intended as a balancing gesture to offset Soviet suspicions about the visit here next week of Chinese Vice Premier Teng Hsiaoping.

The administration has been taking special pains to reassure Moscow that Carter's decision to establish relations with Peking does not represent a U.S. attempt to "play the China card" -- a phrase used by diplomats to describe a strategy of fostering tensions between the two communist superpowers.

Looked at in this way, the sources said, the Press mission has special significance because Press led a group of 12 top U.S. scientists to China last summer shortly before his parallel visit to Moscow was canceled.

Teng is expected to sign a scientific and technological agreement while here. Sources point out that the timing of Press' trip should have a further balancing effect on the Soviets because he will be going to Moscow as the U.S. cochairman of a joint commission on scientific cooperation established under a similar agreement with Moscow.

In addition, the sources said, the United States considers the joint commission a valuable channel of communication with Soviet scientists and is concerned about it falling into disuse.

The commission is supposed to meet annually. However, because of last summer's cancellation, there have been no meetings since July 1977. State Department spokesman Hodding Carter said yesterday, "It was recognized that there would have to be another meeting to keep this going."

Press' cochairman at the Moscow meeting will be Soviet Deputy Prime Minister Vladimir Kirllian. Carter said the meeting will review the effectiveness of U.S.-Soviet exchanges in the scientific area and explore new areas of potential cooperation, such as heat and mass transfer studies and earth sciences.