In 1948, before Mao Tse-tung and his forces took control of China, there were a thousand Christian clergymen of Korean origin ministering to the Korean minority in China, the Rev. Kim Sung Ha said during a recent visit here.

But the Mao revolution, which unified China, turned churches into factories and scattered congregations and clergy alike, and today, Kim believes, he is the only one of those Korean Christian leaders to have survived the successive revolutions that swept China.

Kim, 70, who practiced internal medicine in Chinese government hospitals while he waited the changing political winds that would permit him to return to his religious vocation, has just completed a 10-week tour of the United States. The purpose of the visit, which had the sanction of the Chinese government, was to raise money to establish a seminary in China's Yanbian region to train Korean Chinese clergy.

There are 3 million chosenju, as Korean-Chinese are called, living in China, most of them concentrated in southern Manchuria, Kim said. About 6,000 of them are Christians, scattered among 130 congregations, with only two ordained ministers, he said.

"When freedom of worship was resumed in 1979, small churches mushroomed in every corner of China," he said, adding that the government returned for church use some of the buildings that had been confiscated earlier.

Overall, he said, there are more than 3,000 Christian churches in China, with 13 theological schools. But none serves the Korean ethnic minority.

He explained that it is crucial to set up a seminary in China for the training of Korean Chinese, since Chinese law forbids importing missionaries from abroad.

While the present government welcomes foreign investment or commercial enterprises, outside religious influence is frowned upon, he said.

The Chinese government also disapproves of denominational divisions among Christians. "To the officials of the Bureau of Religious Affairs, a Christian is a Christian," Kim said.

Kim, who met Vice President Bush and a number of congressional leaders during his visit to Washington, said his U.S. tour marked the first such enterprise permitted by the Chinese regime.