Here at Peking University, where tree-shaded lanes and dirty snow give an Ivy League flavor, one of the last decade 's great social revolution lies dead or dying.

After years of leading an attack on privilege and ambition in the world's most populous nation, the students here have settled by back to a lefe of hard study, leading to important jobs and many fringe benefits.

Raucous wallposters demanding all kinds of social changes, many of them demanded by youths who failed to get into China's number one university, decorate main streets of downtown Peking. But there are no such posters out here on the campus in a quiet suburb. Here we are just working hard all the time," said Deng Ling, 22, who studies English and who hopes for permission someday to travel to the United States.

In 1966, wallposters on this campus fired the first salvo in chairman Mao Tse-tung's war against bureaucrats too fond of their staff cars and against students too interested in high marks, to the determent of less privileged or talented members of society.

The campaign threw the country into turmoil Students traveled about China spreding Mao's message while the university closed for four years.

Now university adminstrators frown on those days. "We want to create this as a center of education and scientific reserch to train a nuber of high-level officials for our country," said university administrator Chao En-pu, an intense young man with crew cut and think-lensed glasses.

Enrollment, which stood at 10,800 in 1965 and zero the year after, has climbed back up to about 8,000 Nee Mengisiung head of the university president's office staff, said he was not concerned that those thousands showed little interest in adding to the current outpouring of critical wall-posters. "In my view, wallposters are not the only way, or even the best way, to express one's opinion," he said.

The contrast between the busy silence of this campus, with libraries filled and teachers respected, and the pungent posters still drawing hundreds of readers in central Peking, suggest the old Chinese debate over class and privilege remains unresolved.

Scholars have run this country for centuries. Chinese have always seen education as a way to escape a life of backbreaking phsical labor. Professors used to grow long fingernails to show they did not work with their hands.

Mao and the rest of the Communist party fought to change this atitude, although only Mao and his closest supporters wished to go so far as to insist that the universities be gutted and all the students sent for long spells of farmwork. Today, students and faculty retain a respect for the lives of the workers and peasants who are, in many cases, their parents. But they have different plans for themselves.

In a way, university administrators here are camouflaging the old class distinction Mao used to isolate the privileged classes. Intellectuals, meaning teachers, scientists, journalists and other professionals, were singled out. Under Mao they were sometimes discriminated against in job assignments and admissions of their children to universities.

The new system has given youths with book-conscious parents, or youths who live in cities with rigorogus high school curricula, great advantages when taking the all-important national exam for university entrance. A score of 300 out of a possible 500 on the demanding exam, revived only since Mao's death in 1976, qualifies a student for at least some college. Peking University usually only takes students who reach the 400 level.

Peking youth who failed to reach that leavel in this year's exam are accommodated at special day colleges where they can study while living at home. A designation that they are only associate, and not full members of the university, goes on their record. About 18,000 such students started studying in Peking this year. The system saves them from unemployment or work in the countryside, where living conditions have led serveral youths to put up complaining wallposters in Peking.

Even troublemakers are not permanently ejected from this comfortable campus. Apparently 30 of the 39 members of a writing group called "Two Schools" which wrote articles for Mao's wife, Ching Ching, were members of the Peking University faculty. Chiang was purged shortly after Mao's death and the writing group accused of trying to attack his successor, Chairman Hua Kuo-feng, in any ongoing campaign to discredit veteran officials.

After some reeduction, however, all of the offending factulty members are back at their work her, delving into various scholarly and scientific topics, administrator Chao said.

For the rapid modernization of the economy, China needs brains, so the students and faculty of Peking University are offered the rewards of good careers, perhaps with better housing and schools for their children.

About 60 percent of the students study science. The university plans to expand to 20,000 students by 1985, a remarkable investment in education although university officials seem unable to provide precise budget figures.

For Chinese young people who used to tour the country spreading Mao's word, spending long hours in study is not so bad considering the stimulating assignments ahead.