Chen Xinghua is running a tailoring shop that could make her one of China's richest citizens, or one of its sorriest.

At 28, she is a "new capitalist" who was given official blessing two years ago to invest money in her own business, operate virtually free of government control, hire and live off the labor of employes and even keep all the profits.

Her Peking shop now nets her more money each month than many workers earn in a year, and it has provided her with many luxuries, ranging from a motorcycle to a washing machine, that make her the envy of her friends.

Chen is part of an experiment that could rearrange China's urban social structure, labor force and life style as much as any policy since Mao Tse-tung socialized industry and commerce in the 1950s.

Chinese economists predict that as a result of a recent government directive almost all of the 50 million new job-seekers this decade will end up working for themselves or for privately financed groups, known as collectives.

Although China's huge, centrally planned state sector is to remain dominant, the new collective and private enterprises are expected to play an important supporting role supplying consumer services and goods that are in high demand in what is emerging as a more dynamic, mixed economy.

New entrepreneurs already have multiplied with quiet government encouragement. Of China's 105 million urban workers, 1.5 million--about twice the number of a year ago--are now self-employed, while at least 20 million work for collective shops and factories.

If the experiment lasts, Chen and millions like her could form a new class of merchants, artisans and craftsmen with an unusual degree of wealth and personal freedom in an otherwise poor communist society.

On the other hand, they stand to lose everything should their material success spark a social backlash or should the government revert to the Maoist ideals of egalitarianism and revolutionary fervor that have guided China for much of its 32-year communist history.

Just a few years ago, small entrepreneurs were persecuted for being "evil speculators," and the radical impulse to make China a classless society still lives on in the hearts of some communist officials.

But Chen says, "I really don't worry about being a capitalist. I'm just following the party's policy. Everybody who reads the newspaper knows that. If the policy changes, I won't be happy, but I'll still have money left from my days as a small capitalist."

Chen's story may sound petty to the land that spawns Rockefellers and duPonts, but it is nothing less than spectacular in China where three of every four urban workers toil at government jobs assigned by the state, draw fixed incomes paid by the state and try to fulfill production quotas set by the state.

Mao believed that a communist government should guarantee everyone a job for life whether he wants it or not.

His successors now say that this policy of assuring state jobs--known as "the iron rice bowl"--not only breeds sloth and incompetence, it is impossible to execute in a nation where about 20 million people are now jobless, where 5 million urban youths enter the labor market annually and where up to 20 million workers are filling redundant slots.

While labor productivity dropped by more than 5 percent during the first nine months of 1981, 13,000 industries run by the state lost almost $3 billion because of waste, poor planning and incompetent management, according to China's Finance Ministry.

Although the party has tried to improve morale and productivity with bonuses, wage increases and other incentives, it decided that the more dramatic gesture of refusing to guarantee jobs for future applicants was necessary to break the iron rice bowl.

Last November, Peking abruptly called a halt to Mao's patronage system. The government said it reserved the right to place a select few in state jobs, but encouraged everyone else to "get organized on a voluntary basis or find work for themselves."

In American terms, the decision was as radical as would be an executive order to abolish Social Security.

After three years of quietly promoting free enterprise, Peking suddenly burst forth with an official imprimatur and a package of inducements for the self-employed including tax exemptions, low interest loans and hiring rights.

Xue Muqiao, a senior economic planner, and others believe the new laissez-faire policy will reap big benefits not only in soaking up China's excess labor, but also in releasing the productive energies of the long-stifled Chinese workers.

The state sector with its command of heavy industry will retain its current size through replacement hiring, but for the first time it will be accompanied by a large entrepreneurial service sector whose employes will have every incentive to work hard.

Even if state-run plants remain sluggish, economists argue, the emerging private and collective enterprises will raise overall labor productivity.

The greatest growth is expected for collective enterprises, which pay workers on the basis of their production and kick back a substantial portion of their profits to the government as taxes.

Despite their financial benefits, collective and private jobs still carry a social stigma because of past political campaigns aimed at capitalists and "rightists." Many Chinese prefer the security of a job guaranteed for life in a state-run factory with its accompanying benefits of insurance, housing and pension.

Others have responded to the new challenge with the excitement of a gold rush.

Some workers at state enterprises, hearing about the bonanzas possible for self-employed artisans, even have risked heavy fines by taking long sick leave to set up private businesses, according to Chinese labor sources.

The promise of striking it rich serves as a powerful magnet for ambitious Chinese today, but economists caution that the number of success stories may diminish as the market fills up with entrepreneurs offering the same product and competing for the same scarce supplies.

Enthusiasm still runs high, however, and the relatively few new business operators have begun livening up China's gray cities with consumer services missing since Mao drove out such "capitalist tails" in the 1960s.

A collective restaurant in Peking called the Phoenix fashions itself as a Western bistro complete with coiffed waitresses and disco music.

Residents of the northeastern city of Harbin can now choose from thousands of private doctors, dentists, cobblers, barbers and bicycle repair shops.

Canton's streets are bustling with shoeshine boys who are willing to negotiate a price, peasants selling fresh fruit and vendors offering a peek at a movie viewer.

The rags-to-riches story of Chen Xinghua neatly sums up the hopes and fears of China's born-again capitalists.

A "little Red Guard" who was sent to the countryside during the Cultural Revolution in the 1960s, she returned to Peking 10 years later without work, education or skills.

Jobless for six months, she borrowed $50 from her parents to buy thread, ruler and scissors and set herself up in a closet of her father's home with a hand-me-down sewing machine and an idea.

On Oct. 5, 1979, Chen posted 10 handwritten signs on utility poles announcing the opening of her shop. The next morning, two customers arrived with cloth in their hands, and the flow of business has not slackened since.

Today she earns $200 each month--about 10 times more than the average urban wage--presiding over a newly built shop staffed by two young apprentices and a part-time employe.

Her business not only has reaped enough money to buy everything Chen has ever wanted, it affords her a rare freedom to control her activities. As her own boss, she chooses her own work hours, sets her own prices, hires whomever she likes and does business with her favorite wholesaler.

"I never ask anyone's permission to do anything," said Chen, reflecting an unusual individualism in a society tightly controlled by the state.

New freedom and wealth carry big responsibilites as well for the young woman who works a long day and brings home her books to balance at night. She has had to work double shifts for weeks at a time to meet customer demands, Chen said.

"It's pressure all day," she said, "but I like the idea of being able to earn more if I work more."

Like all good capitalists, Chen wants to expand. She plans to buy electric sewing machines to replace the less-efficient foot-powered ones, install a new steam presser, possibly build a second floor onto her shop or even open another branch.

Here comes the rub.

Communist leaders who have turned to free enterprise to help revive a slumping socialist economy are still uncertain how far to let the experiment run. Some orthodox Marxist officials reportedly believe it already has gone too far.

Publicly, economists insist that the private and collective businesses that have begun to mushroom will be reincorporated into the state system once the unemployment problem fades away and the economy takes off.

Privately, they concede the contradiction of using free enterprise to rev up production only to abandon it once the economy begins to hum.

They admit the allure of high incomes, but minimize the threat to socialist morality because of the large number of Chinese who still favor security over affluence.

They discount the danger of a radical renaissance, yet ominously warn that the party will prevent the emergence of a new class of wealthy capitalists if they do too well.

"This will never create a long-term obstacle to socialist ownership," said a Chinese journalist.

While Peking charts its course, it has placed some limits on people like Chen. No more than five apprentices and two full-time workers can be hired by each self-employed entrepreneur. Private businesses are restricted to one location.

Any official ambiguity causes concern for the capitalist pioneers who say they fight daily discrimination from wholesale suppliers and shakedown demands from local officials. A social stigma still prevails, they say.

Chen said she would rather be known as a "model capitalist worker" than a necessary evil.

"I am a capitalist in a socialist country," Chen said. "I work for China at the same time I work for myself."