The Carter administration has approved more than 400 export licenses for sale of advanced U.S. electronic gear and military support equipment to China, the head of a U.S. Defense Department delegation said here today.

U.S. Under Secretary of Defense William Perry also said he told Chinese officials here that Washington "would look favorably" on Chinese purchase of a sophisticated geophysical data computer with some military application that is more sophisticated than anything so far sold to the Soviet Union.

In turn, Perry said, the Chinese indicated willingness to sell to the United States scarce metals such as titanium, vanadium and tantalum used to make aircraft.

Among the sales to Peking being considered, Washington reportedly has granted Lockheed permission to negotiate the commercial sale of C130 transport planes, used also by U.S. armed forces. Boeing has permission to pursue talks on sales of CH47 Chinook helicopters.

Perry's talks here appear to underline the willingness of both sides to explore their military relationship and its potential impact on adversaries such as the Soviet Union, without actually forging any kind of alliance. The Chinese hope they will pave the way for the day when they can buy U.S. arms.

Perry, leading a two-week tour of Chinese military installations in Peking and other cities, said the Chinese leaders appeared pleased by the progress in Sino-American military exchanges but still pressed for an end to the U.S. ban on the sale of lethal weapons.

The 400 items so far cleared for export by officials in Washington range from small electronics gear to construction of a multimillion-dollar plant for production of American-designed helicopters in the north-eastern Chinese city of Harbin.

New Carter administration policy allows American companies to sell China what is called "dual use" technology, meaning equipment such as computers that have both civilian and military uses. Transport aircraft, radar systems and communications gear may also be sold to China, but lethal weapons are banned.

On the subject of buying tanks, antitank weapons or advanced fighters, apparently high on Peking's shopping lists, the Chinese have been "very polite to us," Perry said. "They have not subjected us to what I would call pressure. They have simply restated the point . . . that they are looking forward to the day when our policy guidelines are broadened to encompass transfer" arms.

Perry said talks began today on possible Chinese sales of titanium and other metals useful in airplane manufacture. He said the Chinese have "vast supplies" of the lightweight, heat-resistant metals, which are scarce in the United States, and they say they might negotiate long-term supply contracts.

Perry, who is the Pentagon official in charge of research and development, said the talks were in a very preliminary stage and that he could not estimate how much metal the Chinese were willing to sell. Officials traveling with Perry said this would represent the first military-related sales by China to the United States.

A new major computer system to be made available to the Chinese, Perry said, is designed for analyzing data from seismic surveys in the search for oil and other useful minerals. The supplier, Western Geophysical Co. of Houston, has tried for more than a year to secure approval for sale of computers and associated technology to China. Up to now they have been stymied by the Carter administration's former policy of not giving the Chinese more than is given the Soviets. Officials noted that the sale must still be cleared by American allies in Western Europe.

Fewer than 20 of the export licenses issued for sales to China involve military support equipment such as trucks and helicopters, officials said. These appear to include a project by Bell Helicopter Textron helicopters to China, to set up a factory in Harbin in cooperation with the Chinese.

The Chinese, who have been slow to buy weapons abroad and do much window-shopping, appear to want to learn as much about new weapons technology as possible without buying too many actual weapons. There have been few actual sales by American companies.

Perry said, "We have encouraged the Chinese to move from talks to action in their negotiations with U.S. industry about imports of American technology." He said his group will also visit electronics, computer and heavy industry facilities in Xian, Nanjing, Hanzhou and Sanghai.