Weinberger in China. Pentagon chief's visit to discuss global and regional security issues comes when US-Chinese relations have begun to cool

US Defense Secretary Caspar Weinberger's visit to China this week comes at a time when political and economic relations between Peking and Washington have begun to cool a bit following the honeymoon that began in the early 1980s. The Oct. 7 through 11 official trip is a continuation of the irregular, but nonetheless high-level, visits that have characterized the diplomatic relationship between the United States and the People's Republic for the past several years.

``The two countries tend to send each other senior people,'' a US official said. ``That does not mean the secretary's visit is primarily focusing on defense,'' he added.

Nevertheless, Mr. Weinberger travels to China at the invitation of Chinese Defense Minister Zhang Aiping, and the US defense secretary is expected to confer with his hosts on a number of ``important global and regional issues of mutual concern,'' according to the US Embassy here.

Those issues will almost certainly include Soviet support for the Vietnamese-backed regime in Cambodia, the Soviet invasion of Afghanistan, the Iran-Iraq war, and the continued growth of Soviet military power in Asia.

Between Friday and Saturday, Weinberger is scheduled to fly from Peking to Kunming, in Yunnan Province. Along the way he is expected to make stops at an unspecificed number of Chinese military bases, according to US officials here. He may also visit a rocket-launching facility on the trip.

During his stay, Weinberger may also attempt to sound out the Chinese on a number of issues not to Washington's liking.

For one thing, Soviet overtures toward Peking have become more pronounced since Soviet leader Mikhail Gorbachev announced in July his country's intention to heal the 25-year-old Sino-Soviet rift.

Yesterday, China and the Soviet Union began a new round of talks aimed at normalizing relations. Deputy Foreign Ministers Qian Qichen and Igor Rogachov are leading the two delegations in the ninth round of negotiations that are meant to resolve political differences dating back to the ideological split of the early 1960s. The talks are expected to last about a week.

Moscow and Peking are also preparing to discuss their border disputes for the first time in nine years and are making strenuous efforts to increase their bilateral trade.

At the same time, China's promise as a vast domestic market for US consumer goods, coupled with its large and theoretically cheap labor force that could be utilized in Sino-US joint-venture projects, has failed to become a reality. Bureaucratic red tape and rising business costs have tarnished China's allure for US businesses.

Moreover, the problems of such joint ventures as American Motors' Beijing Jeep Corp. in Peking have been well-publicized. And senior US officials, such as Amb. Winston Lord, have become more outspoken about China's deficiencies as a business partner.

China, on the other hand, believes that the defense technology that it would like to buy from the US -- avionics equipment for 50 jets and General Electric turbines for its naval vessels, among other items -- is overpriced.

In addition, though Peking is expected to spend between $300 million and $400 million over the next five years to upgrade China's stock of weapons, some defense analysts argue that China will not now want to alienate the Soviets by buying US weapons.

China insists that the single biggest obstacle in relations between the US and China is Taiwan. Peking would like to see the US help it in its propaganda campaign to woo Taiwan into the mainland fold.

Senior leader Deng Xiaoping recently made a public statement that America should use its influence to promote better communications between Taiwan and the mainland. Peking is also unhappy with Washington's proposed arms sales to Taiwan.

Still, the visit could produce at least one breakthrough announcement. Weinberger's arrival in China may be timed to coincide with an announcement of a Chinese port call by US naval vessels. Such a visit was postponed last year after a controversy over whether such vessels would be carrying nuclear arms. China has a policy of not permitting visits by foreign ships armed with nuclear weapons.

On Sept. 30, the eve of China's National Day, during a celebration in the Great Hall of the People, Defense Minister Zhang told foreign reporters that a US naval port call may occur in November. He gave no other details. US officials in Peking were not immediately available for comment.

As a result of the successful visit of two British Royal Navy warships to Shanghai last July, a US official said, an American warship visit to China could occur ``in the near future.'' The official added that negotiations between the US and China concerning the visit have never been formally cancelled.