Ma Po was born into an intellectual Chinese family and later labelled an "active counter-revolutionary." So, despite his top grades in high school, he was sent to Inner Mongolia instead of college in 1966.

Now, at 30, he has been allowed to enroll as a freshman at prestigious Peking University.The change in policy has been so radical and sudden it has brought the first rumblings of a real grassroots challenge to the policies of China's new leaders, the successors to the late Communist party Chairman Mao Tse-Tung.

An official radio broadcast from Anhwei Providence monitored here reveals that some education officials have charged that "the new enrollment system does not represent the interests of the working class and the poor and middle-level peasants and runs counter to the party's class line."

Other recent broadcasts and official articles have also hinted at new attacks of the educational system, the starting point for much political turmoil in China in the last two decades.

"The new education system is clearly the most serious point of controversy in China today," said one analyst here. Travelers who have talked to foreign students studying at Peking University say there are continuing signs of tension between upper classmen who were selected on political grounds and the new class being admitted on basis of test scores. "The worker-peasant students are not happy with the new breed," said one foreign traveler.

Ma Po, a Chinese mayor at Peking University, was among only 278,000 to gain admittance to universities out of 5.7 million who took entrance examinations. The exams were a key part of the sudden change in the school system. During the last six years of Mao's life, according to officials' statements at that time and refugee interviews, many children of worker and peasant families who did not perform well in tests were still admitted to college because of their class background and political fervor.

Although the Chinese have not published figures comparing the numbers of workers and peasants enrolled under the Maoist and post-Mao systems, the few statistics available seem to indicate they are not getting a share of the population. Heilungkiang reported last month that 59 percent of new college students in the province were children of workers and peasants. Worker and peasant families were estimated to make up at least 80 percent of China's population.

In a sharp criticism of the new system, educational officials in Anhwei, who apparently perceive a trend against "laboring classes," said, "enrolling hundreds of thousands of students has offended tens of millions of students."

"If such things go unchecked," they said to colleagues supporting the changes, "we would like to see if the poor and the lower-middle peasants will oppose you." The Anhwei braodcast derided critics of the new system, but still acknowledged their existence.

Chinese leaders, particularly party vice chariman Teng Hsiao-ping, have argued that universities must raise their academic standards if China is to modernize its economy rapidly. In a series of somewhat defensive articles, Peking newspapers and journals in recent months have argued that peasants also workers are not being shortchanged even though the new examinations emphasize academic skills rather than family background.

A recent New China News Agency dispatch said priority is given to workers or peasant youth if they have equal marks" on the examination compared to young people from other social backgrounds.

Yet, the 85 percent of Chinese youth who live in peasant villages and communes are at a great disadvantage in obtaining equal marks in the tough college entrance test. A Chinese child growing up in a large city is usually guaranteed a place in senior high school. In the countryside there are not enough senior high schools for everyone and those that do exist the equipment and teachers are not as good as the urban schools.

"Socialist society is still not communism and the differences in the level of education between rural and urban schools, a relic of history, still exist," the official news agency said."The gap is being narrowed step by step, but the only way to eliminate it completely is to develop primary and secondary education inthe rural areas and raise their educational standards . . . It cannot be done by changing the principle of selecting the best students."

Ma Po's mother is a novelist, his father a university administrator Like many intellectually inclined party members, they were both severly attacked during the Cultural Revolution of the late 1960s. Their son was similarly punished by being sent to work for five years in an Inner Mongolian rock quarry. In a recent Peking review article he recalls the day he was finally exonerated: "I was so overjoyed that I rushed outside and ran wildly about and rolled on the snow."

Since Mao's death, Peking's new educational leaders have argued that students like Ma really do come from "laboring families," even if it is mostly "mental labor" that his parents perform. But an article in Peking's Kwangming Daily recently disclosed that some delegates to a national educational conference were saying "there are already too many children of intellectuals" among college entrants and that "the children of poor and lower-middle peasants have not been given special consideration."

The official breakdown of college enrollment for this spring, when the first group to pass the new examination entered university, said 87 percent were from "families of workers, poor and middle-level peasants army men, cadres or intellectuals." That leaves at least 13 percent from social groups that in the past have been victims of officially sanctioned discrimination, such as former rich peasants, landlords and capitalists.

In sharp contradition to the old Maoist calls for class struggle, the new educational administration has been apparently trying to soften the old hard class lines. One recent report from Kwangtung Province told of a youth whose "grandfather was a landlord and mother was guilty of graft." But the boy got such a high mark on the entrance exam and had worked so hard in the countryside that official resistance to his application was overcome.

The Peking Review article on Ma Po repeatedly sought to emphasize the energy he had devoted to his work in the rock quarry, and later at a factory in the border region. "My fellow workers said to me, 'Ma Po, don't forget us workers when you become a student,'" Ma said in the article. "No, I shall never forget. I'll study hard, and do my bit for the motherland."