The Chinese government, apparently troubled by a series of Peking rallies criticizing aspects of its rule, has moved vigorously to end public demonstrations and discourage unofficial Chinese contact with foreigners.

Diplomats in Peking reached by telephone said Chinese had been told at special meetings Wednesday evening in their offices and factories that the impromptu "democracy movement" would have to slow down. Foreigners who tried to continue freewheeling sidewalk talks they had enjoyed earlier in the week found many Chinese cautious and sometimes hostile after the Wednesday warning.

A Western diplomat who approached Chinese late Wednesday in Peking's Tienanmen Square, where 10,000 people heard a series of prodemocracy speeches Tuesday night, said, "People were very nervous. One Chinese told me, "There are a lot of plainclothesmen here tonight, and people just don't want to talk.'" Foreigners reported similar tension in sidewalk contacts with Chinese yesterday and today.

Top officials of the Chinese Communist Party, who are reported to be holding an important meeting, may also fear the possibility of clashes between demonstrators criticizing the arbitrary rule of the late Chairman Mao Tse-tung and defenders of the legendary Chinese leader. After more than a week in which wallposters criticized Mao for temporarily purging pragmatic officials like Vice Chairman Teng Hsiao-ping, new wallposters near the Peking Hotel yesterday struck back vehemently at Mao's critics.

Diplomats said one poster labeled those calling for more democracy as "Soviet revisionists." It criticized those who attacked Mao, and by association, Mao's successor Chairman Hua Kuofeng.

The street-corner democracy movement suddenly began about two weeks ago after the leadership declared a 1976 riot in Tienanmen Square to be a "revolutionary event." This cast doubt on a decision made by Mao at the time to punish the April 5, 1976, rioters and on a followup decision to purge Teng and make Hua the heir apparent of Mao.

Another poster attacked the recent pro-Teng and anti-Mao demonstrators as "bad eggs" and "dogs' heads." Such terms were used by Red Guards attacking party officials during Mao's Cultural Revolution 10 years ago. Using a once-favorite solar symbol for Mao, the poster said, "We should exercise dictatorship over this small group who dare to attack the red sun in the hearts of hundreds of millions of people."

Although rallies have been curtailed, there is little sign yet that posters covering walls in several parts of the city have come down, diplomats said. They said they thought new posters were appearing less frequently than before, however.

One diplomat said a Chinese told him the official warning read at his special unit meeting said, "The movement was going too far too fast." The man's version of the 6 p.m. Wednesday meeting at his unit seemed to underline warnings issued in the official press earlier by Teng himself.

"They said we should not carry criticism of Mao too far. We could still have meetings and discuss democracy, but only if we were careful to 'seek truth from facts,'" the Chinese said, repeating the slogan Teng has enshrined as the keynote of his effort to free Chinese economic and social policy from Maoist dogma.

This new pragmatism has led China to rapidly expand its foreign trade, once frowned upon by Maoists bent on self-reliance, and return to a system of advancement in schools and factories based on brains and productivity, rather than on political reliability.

The official press reinforced Teng's call for "stability and unity" today. The front page of the People's Daily this morning had an article praising workers at Peking's Capital Iron and Steel Factory for carefully studying Teng's recent published comments praising Mao. Teng also noted that "some utterances are not in the interest of stability and unity and the four modernizations" -- of agriculture, industry, science and national defense. "We have to explain matters clearly to the masses and know how to lead."

A dispatch by the offical New China News Agency today told how several demonstrators cleared after their arrests in the 1976 riots were now spending all their time on work projects, such as building computers or furniture. The article said nothing about the latest rallies in Tienanmen Square.

One foreign diplomat said that although Chinese in the streets are now more cautious, it is still possible to have conversations with them. Several diplomats said they thought the situation was still volatile, with many Chinese waiting for an announcement of the results of the reported high-level party meeting to see what the government's policy would be.

Several posters remained on Peking walls criticizing some current members of the ruling Politburo for supporting Mao and suggesting that several purged Mao foes be brought back to power. Diplomats have been expecting some indication of at least a slight reshuffle of the Politburo, despite recent Teng comments debunking such speculation.

Authorities are understandably reluctant to remove forcibly posters they do not like. It was the premature removal of wreaths and poems honoring the late premier Chou En-lai that precipitated the 1976 Tienanmen riot, in which scores of people were injured and several vehicles and buildings were burned.

In the meantime, Peking sources said the unit meetings throughout the capital were being read excerpts from a 19-point Central Committee document giving detailed advice on what should and should not be done in wallposters and public statements, including advice not to criticize Mao by name.