Long initial conversations between Chinese officials and Treasury Secretary W. Michael Blumenthal, here to set in motion new trade and commercial relationships with Peking have gone smoothly, a senior spokesman for the U.S. side said today.

In talks between Blumenthal and Yu Chiu-li, China's vice premier for economic planning, some progress was made toward the settling of claims by U.S. and Chinese citizens for assets seized by both countries at the time of the formation of the Communist government in Chma, the U.S. spokesman said.

Meanwhile, a spokesman for the Chinese Foreign Ministry told reporters accompanying Blumenthal that the fighting between China and Vietnam should have no effect on either Blumenthal's mission or China's economic goals. "But if we let them move provocatively on the border all the time, it would affect our modernization," the spokesman said.

Vice Premier Yu will be cochairman with Blumenthal of the overall U.S.-Chinese joint economic committee that is to supervise the broadening U.S.-Chinese economic relationship.

The American side is pleased with Yu's appointment, a spokesman for Blumenthal said, describing Yu as "the most senior economic man in the Chinese government."

Yu was quoted as saying that the extent to which China could pay for imports of capital goods would depend on the form of foreign investment in China. He said that if substantial joint ventures and compensation agreements are made, it would provide China the foreign exchange with which to import many types of products. Joint ventures are equity deals, in which a foreign company owns a share of a business.

A compensation agreement provides for the foreign company to take its payment in the product produced. Yu singled out rare materials as candidates for compensation deals.

Although equity deals have been mentioned before, this is the first time they have been proposed in government-to-government contacts, a spokesman said Most of the American commercial dealings with China announced so far, including proposed oil exploration, have not involved equity deals. For example, hotel consortiums building tourist accommodation have management contracts, and will eventually turn over the hotels to the Chinese. Similarly, the deal made some weeks back by the Coca-Cola Co. involves building bottling plants that eventually will be turned over to China.

Joint ventures would mark a new and potentially more advantageous investment possibility for many American firms.