Concern mounts over mysterious disappearance of Chinese-American

Dr. Ye Lifa has disappeared.

Two years ago, Dr. Ye, who holds both Chinese and American citizenship, was one of Shanghai's best-known intellectuals. He lectured at academic institution after institution on his experiences in the United States, which he had visited in 1979 after an absence of 13 years. On one occasion, his audience reached 14, 000.

Today, Dr. Ye has not been seen in public for more than four months. No one answers the telephone in his apartment. Worried friends who have made discreet inquiries have received no solid information. But several of them are convinced he is being held under some form of detention.

Precisely what Dr. Ye did to run afoul of the authorities is not known. Some of his friends believe that he may have too flamboyantly neglected a warning that he should cease public contacts with Americans. His lectures, incidentally, had a patriotic theme: that this was the time for Chinese intellectuals overseas to return home and help their fatherland.

Dr. Ye comes from a well-to-do Shanghai family and went to the US to study in the 1930s. During World War II, he enlisted in the US Marines, becoming an American citizen after the war.

He took his doctorate in engineering and became a professor of hydrology at the University of Iowa. But in 1966, when he received word of this father's death in Shanghai, he returned to China to fulfill his filial duty and attend his father's funeral.

This was just after the Cultural Revolution had broken out. Dr. Ye was arrested as soon as he crossed the border from Hong Kong into Shenzhen (Shumchun). He spent the next 11 years in the Baimaoling labor camp in Anhui Province. He was not released until 1977, after the fall of the ''gang of four'' headed by Mao Tse-tung's wife, Jiang Qing.

After his release, Dr. Ye told friends that the authorities had confiscated his US passport and his other possessions, including a key with Greek letters signifying that he belonged to a hydrological fraternity. The authorities used the key, Dr.Ye said, as proof that he was an agent for the Central Intelligence Agency.

Dr. Ye apparently harbored no bitterness toward China because of the treatment he had received. He refused an offer from the authorities to reimburse him for the salary he would have received during the years of his incarceration, and accepted a research job studying sedimentation in the Chang (Yangtze) River estuary. He was given a secretary, a telephone, and a salary of 200 yuan (about

Dr. Ye never renounced his American citizenship, but the authorities did not return him his American passport, and in 1979, when he returned to the US, he did so on a Chinese passport.

He lectured widely on his experiences in China, taking a basically sympathetic attitude toward the new Chinese leadership under Deng Xiaoping and toward the goal of modernizing China in the next 20 years.

Back in China, he gave more lectures, this time on what he had found in the US. These lectures were given considerable publicity in the official news media.

But from about two years ago, the official attitude toward him seems to have cooled. Dr. Ye was quite open about cultivating friendships with Americans, including official Americans, and did not end these relationships even when told to do so. He told some friends that he was doing nothing illegal, and that he was certain the bad old days of arbitrary arrests were over.

In 1981 Dr. Ye applied for permission to make a return visit to the US for another series of lectures at places such as the University of South Carolina, Louisiana State University, and the University of Iowa, all of which had invited him to visit their campuses. But the authorities did not give him the Chinese passport that would have enabled him to make the trip.

Toward the end of 1981, Dr. Ye lost his job researching the Chang River estuary and was given a sinecure in a government department dealing with nonparty intellectualism. He continued occasionally to meet Americans until the summer of 1982.

Dr. Ye, who is divorced, has a son and daughter in the US.