The American student had not been in Peking very long when young women in tight white sweaters began to show up at his university's weekend dances.

"They had tailored slacks and heavy makeup, not like Chinese girls at all, but they were. It caused a lot of trouble," he said recently.

For a few weeks, those freewheeling dances earlier this year provided an unprecedented change in the usual austerity governing Peking's university life. In blank dormitory corridors populated by puritanical young Chinese and lonely young Africans and Europeans, sexual and racial incidents broke out that have not entirely calmed cdown, according to several foreign students interviewed here.

At least two women found in foreigners' hotel rooms were eventually artained for a while. The dances were curtailed or more carefully supervised. University officials rushed to smooth over jarring incidents caused by foreign students trying to pick out prostitutes at the dances and making a wrong choice.

China remains one of the most sexually repressive societies on earth. After 1949, when the Communist armies captured China's big cities and closed the brothels, Chinese officials claimed to have succeeded in outlawing the world's oldest profession. As the recent events on Peking campuses show, however, prostitution survives here on a small scale at the edges of society, when loneliness, boredom and poverty overwhelm young women whose futures are so bleak they have little to lose.

"As it was explained to me by one official, these girls at the dances were the daughters of party officials who had been purged. They had been sent to the countryside but came back to the city and had nothing to do, and some trouble in getting enough money to live," said one foreign student.

"They would come to the dances, some of them danced very well, and then would accept invitations from foreigners to come up to their dormitory room. The price I heard was ten kuai." The amount equals $6.37, slightly less than a week's pay for the average Chinese factory worker.

"The problem was that some guys would make a mistake and invite up a girl who had really come just to dance. She thought she was just going up to hear the foreigner's record collection, and when he tried something there was terrible screaming and trouble. I walked in on one of those, and heard another," the student said.

At one university with many American and other foreign students-the Peking Languages Institute-the authorities have said foreigners will no longer have Chinese roommates. The university officials say the reason is lack of space, although some foreign students suggest the government may be trying to tighten control over a student community where many of the prostitute incidents were reported.

At other campuses, such as Peking University, foreigners and Chinese expect to continue to room together.

Many of the Americans studying here have just arrived as part of the first wave of students and scholars to be exchanged between the United States and China. They say the Chinese are friendly and helpful, and that the worst campus tensions arise between the Chinese and the students from developing countries, particularly the Africans.

"Many of the Africans don't want to be here, were sent simply because the Chinese offered cheap tuition to their host countries. They aren't happy, and the Chinese attitude toward them doesn't make things better," said one European student.

Last November, foreign students briefly boycotted classes when Chinese officials tried to deport a Senegalese student who had beaten up his Chinese roommate at Quinghua (Tsinghua) University. The Senegalese had accused the Chinese of looking in his books and taking some of his papers.

The student was told he would be allowed to stay after he wrote an apology, but once the furor died down, he was quietly sent home anyway. In April, a mob of Chinese students reportedly attacked African students at the hydraulic institute at Nanjing, about 600 miles southeast of Peking. The Africans had protested a wallposter put up by Chinese that made allegedly racist arguments against allowing "penniless" foreign students to fill up cherished Chinese college spaces.

Few of the African students here are women, creating a difficult social problem. Many Africans along with other foreign male students welcome the arrival of prostitutes, but from the Chinese "there were many complaints," a student said at the time.

There have been other reports of prostitution in China.

American researchers Mirian and Ivan D. London have published the transcript of an interview with a refugee to Hong Kong from Canton. The man gave a second-hand account of prostitution in that southern city. Girls could be found in certain parts of the city wearing Western-style hairdos or colorful badges as identifying marks.

"Prostitutes along Pearl Light Road . . . were called 'roadside chickens'-that's a famous culinary dish in Canton," the Londons' informant said. When a friend sent to the road "saw a few girls answering my description, he called out, "motor!" One of the girls, he said, turned and called right back, "son of a motor!" Such girls are called motors, I think, because a motor always keeps turning."

An emigrant to Hong Kong from a mining community in the northern province of Hopei said many poor mining towns developed homegrown prostitution rings composed of mine accident victims' widows trying to supplement meager incomes.

"They would charge miners who were not married about one kuai (64 cents) to spend the night, and also do their laundry. The authorities knew about it and just told people not to make it too obvious," the emigrant said.

In Peking, foreign students report, the authorities have now cracked down on the most obvious soliciting practices. "There was one guy busted for running a string of prostitutes at the universities and the hotels," said an American student here. "It seemed strange to me. The only reason for a pimp to earn so much money is to buy a big long Cadillac, but you can't get those here."