China appeared to signal its continued interest in improving relations with the United States in the face of a perceived Soviet threat today by signing a final agreement on Sino-American claims and assets.

Peking had delayed signing a final version of an agreement intiated by Treasury Secretary Michael Blumenthal here March 1 because of disputes over details, including a Chinese request for U.S. help in identifying Chinese individuals having money in American Banks.

A press release this morning indicated that the Chinese had dropped their request so that an agreement could be signed before Commerce Secretary Juanita Kreps left here.

Chinese official sources siad Peking has repeated its willingness to talk with Moscow about improving relations, but Vice Premier Deng Xiaoping warned Americans Thursday that no agreements would restrain Soviet "expansionism."

In commenting on China's relations with the Soviet Union, diplomatic sources Thursday said China had again told Moscow that it was willing to discuss such matters as trade and cultural exchanges. This message, the sources said, was conveyed to the Soviet ambassador at a meeting May 5.

Diplomats here said that meeting called to respond to an April 17 Soviet note endorsing the talks, was an interesting development. But they held out little hope for rapid improvement in relations between the two vehemently hostile Communist giants.

Chinese Vice Premier Deng Xiaoping, asked by American reporters here Thursday his reaction to the announcement of a strategic arms limitation agreement between Washington and Moscow, said, "We don't think you should put your trust blindly in any such agreement-not only this agreement but all other agreements will not serve to to restrain the expansionism of the Soviet Union."

Deng spoke after a morning meeting with Kreps. He startled some of the American officials visiting here by bluntly predicting the iniating of a trade agreement before Kreps left China Tuesday.

Kreps and other negotiators said they saw much detail work standing in the way of an overall trade pact, but appeared to be encouraged by the quick wrapup of the troublesome claims and assets agreement. Deng had predicted Thursday morning the claims deal would be signed. Twelve hours later Chinese officials announced that the signing would be this morning.

A press release handed out in the Great Hall of the People as Kreps signed the claims and assets agreement said $30 million would be paid Oct. 1, 1979 to American claimants who lost property in China because of the 1949 Communist victory. The Chinese have agreed to pay $80.5 million to Americans by Oct. 1, 1984. A special commission had recognized 384 claims totaling $197 million

The release said the United States would unfreeze $80.5 million in Chinese assets held in American banks since 1950, but "the agreement does not take any position as to the ownership of those assets." Washington has been reluctant to reveal the names of individual Chinese depositers for fear of political reprisals against them by the Chinese government.

The latest round of proposals between the Chinese and the Soviets began April 3 when Peking announced it would not renew its 30-year-old friendship treaty with Moscow. It instead proposed talks to solve disputes between the two countries. The Soviets responded affirmatively April 17, and Chinese Vice Foreign Minister Yu Chan replied on May 5 to their note, the diplomatic sources said.

The Chinese reportedly proposed no time or place however, forcing Moscow to take the initiative if it chooses.

Sino-Soviet trade has increased substantially over the last several years and occasional talks are held on navigation of rivers on their mutual border, but the diplomatic hostility between the two countries has appeared to grow worse.

Relations have been particularly strained by Moscow's growing alliance with Hanoi and China's month-long invasion of Vietnam's northern border region in February and March.

Diplomats have anticipated that the two sides might sometimes seek to ease tension on their border to cut the expenses of keeping huge standing armies there. Yet the most recent exchange on the question of talks, appeared to analysts here to be little more than an attempt by staunch international foes to show outsiders they are acting reasonably.

In his reply to the question about the Sino-American SALT negotiations, Deng said, "We are not against this agreement, we're not against negotiations," but added that they would not help stop Soviet expansion.

Deng remained firmly optimistic about the prospects for U.S.-China trade. He said the readjustment of China's economic goals was designed to balance economic growth, not slow it down. He said it would have no effect on Sino-American trade, variously estimated to climb $1.5 billion to $2 billion this year.

Kreps leaves Peking this morning for short visits to Shanghai, Guilin and Canton before leaving China for Hong Kong Tuesday. Chinese questions and objections to detailed U.S. requirements in such area as patent protection appeear to have delayed the initialing of the trade agreement.