It's Saturday night at the International Club in Peking, and the crowd is leaping, twisting, twirling -- and in some cases, just stomping on the dance floor.

One woman doesn't actually dance. She bursts into a sprint, and then prances. Another is violently shaking her shoulders. Dressed in sneakers and a red jogging outfit, a male dancer without a partner erupts into motion, doing what appears to be a combination of the samba and jogging in place.

Some of the men wear business suits, but others sport blue jeans and boots. The women seem to prefer jeans, but many also wear smart, western-style dresses. A man dressed completely in white dances with a partner clad all in black, except for her red stockings.

The main dance style: anything goes.

The music: tapes from the West, mostly American rock 'n' roll. Some of it is a few years old. A Saturday night selection included numbers by SSQ, Fake, Linda Fields and Boney M.

Anyone who still has an image of the Chinese as humorless robots marching to their farms and factories ought to see this, the ultimate in hip-shaking, arm-twisting diversity.

A sign at the entrance to the International Club warns that fines will be given to those who throw fruit peels on the floor, tear the floor up with their spiked heels or engage in rowdy behavior -- an indication that things can get rough here at times.

But on this evening at least, no one is breaking rules. It's considered all right to dance in China these days.

The International Club is a special place, of course. It's run by the Chinese government for diplomats and other foreigners, although the great majority of those attending the dances are young Chinese. A ticket to these Saturday and Sunday night dances costs 15 yuan, or $5.35, which is a lot when one considers that the average Peking worker makes 60 to 70 yuan ($21 to $25) a month.

Many of the Chinese who come to these dances appear to be the sons and daughters of the country's elite because of their relatively smart dress and the taxis and motorbikes they use.

Some of those attending a recent dance said they were students. But there was also an elevator operator and a man who said he worked in an electronics factory. The man said he made nearly 100 yuan, or about $35, a month and said he could afford to go to such dances twice a month.

But most Chinese can find cheaper places to dance. Indeed, their work units are likely to be organizing dances and encouraging them to attend.

Nowadays, according to official Chinese publications, everybody's doing it. Travelers report that the dancing fad is not limited to big cities, but has spread to small towns. Hotels in some provincial capitals hold dances every night, with several dances sometimes taking place at the same time in the same hotel.

The usually dour Communist Party officials who are supposed to be monitoring all this seem to have decided that dancing is a good way to let off steam and that disco in particular is not the decadent western activity that they once deemed it to be, but a kind of folk dance. It also turns out to be good exercise, they say.

This liberal attitude began to flourish only in recent months. Dancing was frowned on during the Cultural Revolution from 1966 to 1976. And even as recently as 1983, dancers could run into trouble with authorities cracking down on "bourgeois influence" and "spiritual pollution."

Some observers, such as Liang Heng, a former Red Guard now turned U.S. citizen and magazine editor, see the fate of dancing as a kind of litmus test for the Chinese government's handling of social and cultural freedoms across the board.

"Before, the party organizations wanted to control everything, including the people's use of their free time," said Liang at the end of a recent trip to China from his new base in New York. "To tolerate disco means losing a little control."

But if just about anything goes on the dance floor these days, that does not necessarily apply to all other means of expression. Chinese writers were told at a conference at the end of last year that they could exercise the freedom of expression. But many of them are reported to believe that they might be punished if they went too far in expressing themselves. Any questioning of the leading role of the Communist Party in China is ruled out.

Tapes of songs sung by the popular Taiwanese singer Deng Lijun were once virtually banned here. They are now sold openly in free markets, and her songs are heard everywhere. But two Chinese singers who tried to imitate her style came under criticism by officials for trying to sound "too Western" and "too sexy."

At an American film festival here, the Chinese Culture Ministry censored nude scenes from two of the five films, "Kramer vs. Kramer" and "The Turning Point."

And the British pop duo Wham! recently made an appearance here at the Peking Workers' Gymnasium.

But with China now open to more consumer goods, including tape recorders and cassettes, it's difficult to shut down Western dance music altogether.

Rather than fight the trend, the Communist Party seems to have decided to join it, and even stay ahead of it. The Communist Youth League is one of the most active of the groups now organizing dances.

In a magazine article last month, Deng Liqun, the party's propaganda chief, is quoted as saying, "I have consistently been in favor of organized dancing for young people.

"There were, of course, incidents in the past when hooligans and rowdy young people forced themselves into dance parties and messed things up," said the propaganda chief in the March issue of Research, an ideological-political work.

But, he continued, "the experience of the Peking Municipal Communist Youth League shows that, as long as dance parties are organized and supervised well by the work units concerned and these units organize their own sentries, as long as the people attending these dances are given a little coaching in advance on what is meant by normal socializing and recreation, and as long as these dances are organized, led and guided properly, there will be no incidents."

At the end of 1984, the government launched what was supposed to be a 12-part series of dance lessons on television. The lessons were supposed to include the waltz and foxtrot as well as the jitterbug, rumba and samba. But officials had second thoughts about promoting dancing in this way, and ended the series after running only two parts of the program.

At the same time, the government has used a number of publications to convey the message that dancing is all right as long as it is viewed as good exercise, as folk art and as a means of meeting people.

A writer for the magazine New Observer described in last month's issue how he visited a Red Army veteran and his wife and found them with several elderly friends dancing to disco music.

A veteran of the 7,500-mile Long March was reported to have told the writer, "My daughter taught me how to dance the disco. I feel it's good for the health of old people, just like doing tai ji quan a kind of traditional Chinese shadow boxing and he xiang gong a kind of breathing exercise done while imitating the motions of a flying crane ."

The veteran went on to say there was nothing basically different between disco and a Chinese folk dance called the yangko.

"Disco is an African folk dance, while the yangko is our native dance," he is quoted as saying.

In any case, the official attitude seems to be much more relaxed than it was several years ago when those entering a dance hall in Changsha, the capital of Hunan province, were handed a sheet of written instructions on how to behave. Along with advice about correct demeanor and the need to avoid eating onions and garlic before dancing was the admonition: "Do not give away state secrets on the dance floor."