The United States and China, starting to mend some of the tatters of their military relationship, today discussed improving liaisons between military attaches and possible new exchanges in military education, military medicine and logistics.

A meeting between visiting Secretary of State George P. Shultz and Chinese Defense Minister Zhang Aiping was the forum for broaching the new measures of military cooperation after many months without motion in this field.

The Chinese gave approval only yesterday for the meeting, and the subjects discussed were a far cry from the expansive and high-profile proposals for major arms sales and extensive military cooperation in the final year of the Carter administration and the early months of the Reagan presidency.

On the last trip here by a secretary of state, in June 1981, Alexander M. Haig Jr. disclosed a policy change to allow China to purchase U.S. arms and announced a forthcoming trip to Washington by the vice chief of the Chinese general staff to implement the arrangement. The trip never came off, however, because of Chinese unhappiness with the U.S. position on Taiwan, and Peking has taken no steps to purchase U.S. weaponry.

Since proclaiming an independent foreign policy last fall, China has dropped its previous advocacy of a grand anti-Soviet coalition involving the United States, Western Europe and Japan. As it resumed political talks with the Soviets, China has seemed to pull back from the threshold of alliance with the United States.

There was no indication, according to U.S. sources, that the Chinese are prepared to send a high-ranking officer to Washington to explore an arms supply relationship, though Shultz made clear in his meeting that such a visit would be welcome. The Chinese defense minister also did not respond to a suggestion that U.S. Secretary of Defense Caspar W. Weinberger visit China.

Nonetheless, U.S. officials considered as positive the fact that the Shultz-Zhang meeting took place at all. The Chinese side delayed until yesterday its response to Shultz's request to see the Chinese defense minister, although most of his other requests for appointments were approved much earlier, according to U.S. sources.

The two principals decided, at Shultz's suggestion, that second-level officials should meet later for more detailed discussions. Deputy Defense Minister Yu Jian Zhang was to meet Adm. Jonathan Howe, State Department director of politico-military affairs, and Richard Armitage, deputy assistant secretary of defense, but this session was postponed until Saturday.

In a press conference with U.S. reporters, Premier Zhao Ziyang seemed to minimize the importance of his defense minister's meeting with Shultz, saying, "China and the United States have no military ties."

The next major step to thicken Sino-American political relations is expected to be a visit to Washington by Zhao, and Shultz today presented the premier with a formal letter from President Reagan inviting him to visit in June or September. Zhao made no immediate response, but Chinese sources said September was a much better bet because of the political calendar here.

During the two-hour Shultz-Zhao meeting, according to a U.S. briefing, a wide range of issues including Sino-Soviet relations and U.S.-Soviet relations was discussed.

Reacting to complaints of American businessmen in Peking, some of whom he met in a contentious luncheon on Thursday, Shultz asked Zhao for assistance in providing better living conditions at reasonable cost for U.S. business and diplomatic personnel here. Zhao promised to look into it, according to the U.S. side.

About 10 to 15 minutes of the Shultz-Zhao meeting concerned Taiwan, which the Chinese premier told reporters is still "the main obstacle" to improved Sino-American relations. There was no indication that either side offered anything new.

Shultz also spent 40 minutes with Prince Norodom Sihanouk, former Cambodian head of state and leader of an anti-Vietnamese coalition including nationalist and communist elements.

According to U.S. sources, Sihanouk did not explicitly request U.S. arms aid, though he did express the hope that all friendly countries would contribute arms and training to his cause.

The secretary of state also met Chinese Minister of Finance Wang Bingqian and Vice Minister of Foreign Economics and Trade Jai Shi to discuss various economic issues, including the Sino-American textile negotiations. Shultz expressed readiness to restart the talks.