China and the Soviet Union have agreed that their foreign ministers will exchange visits next year as part of their efforts to normalize relations, diplomatic sources reported today.

The agreement, worked out during the visit here of Soviet Vice Foreign Minister Mikhail Kapitsa this week, marks another step by Peking toward a foreign policy that is more "equidistant" between the Soviet Union and the United States.

In recent conversations with western visitors, Chinese officials have used the phrase "equidistant" and have stressed their view that it is now the arms race between the two superpowers, rather than Soviet expansionism, that is the major threat to world peace. Previously, China had sought to strengthen a strategic relationship with the United States as a counter to Soviet objectives in Asia.

The visit by Eduard Shevardnadze would be the first trip here by a Soviet foreign minister in more than two decades, according to diplomatic sources.

Since he came to power earlier this year, Soviet leader Mikhail Gorbachev has shown increasing interest in China and the rest of Asia. He proposed an Asian collective security agreement this spring.

Kapitsa's eight-day visit to China has improved further the atmosphere in relations between China and the Soviet Union, according to an Eastern European diplomat familiar with the talks. The diplomat said that Chinese Foreign Minister Wu Xueqian would travel to Moscow in May or June of next year and that Shevardnadze would visit Peking in the fall, pushing forward an agreement in principle, reached two months ago, for the visits.

While trade, cultural and diplomatic exchanges between the two Communist nations have been increasing, Chinese officials continue to stress publicly that political differences remain between Peking and Moscow.

But western diplomats argue that Kapitsa's visit here and the agreement on an exchange of foreign ministers are both signs that, Chinese rhetoric notwithstanding, a kind of normalization of relations is taking place.

Foreign Minister Wu said in an interview with the official New China News Agency published earlier this week, for example, that no progress had been made in the most recent round of talks toward removing the so-called three obstacles to "normalization" of relations cited by the Chinese.

The obstacles include the size of the Soviet military force near the Chinese border, the presence of Soviet troops in Afghanistan, and Soviet support for Vietnam's occupation of Cambodia.

Western diplomats also noted that Kapitsa's visit to Peking was accompanied by an unusual list of complaints against the United States, which was given great prominence in the Chinese press today. The diplomats noted that it constituted a record airing of differences at a time when they thought U.S.-China relations were steadily moving forward.

The diplomats in the meantime said they were baffled by the intensity of China's reaction to the recent arrest by American police of a Chinese research scholar in Berkeley, Calif.

According to the U.S. State Department, campus police arrested the student on Nov. 18, suspecting he had been peeping into a girl's dormitory. They later acknowledged having made a mistake in arresting the man. The Chinese government says the police beat the student, but local authorities said they believed the police used no more force than necessary to get him to the police station.

The State Department expressed regret to the Chinese that the campus police had not informed China's consul general in San Francisco.

On Wednesday, a Chinese Foreign Ministry spokesman called it "a grave incident, which constitutes a violation of personal freedom and the safety of Chinese nationals in the United States."

The spokesman also criticized continuing western restrictions on transfers of high technology to China and the U.S. Senate's approval on Monday of a draft proposal that he said made "unreasonable demands" for unilateral changes in the newly signed U.S.-China nuclear cooperation agreement.

Yet another spokesman voiced concern over a proposed U.S. textiles quota bill.

As Peking appears to be making moves that put distance between itself and Washington and that reduce tensions with Moscow, it is also strengthening its ties with Eastern Europe. Vice Premier Li Peng is about to visit Czechoslovakia and Bulgaria. The East European diplomat said Li will stop in Moscow on the way back to Peking.

In his year-end summing up of foreign relations, Foreign Minister Wu paid considerable attention to ties with Eastern Europe and said that China had improved its relations with the Soviet Union "to a certain extent."

Vice Foreign Minister Kapitsa, upon his arrival here last week for talks on international issues, said that "our bilateral relations are improving very rapidly."

The East European diplomat predicted that the Soviets would eventually make a move to reduce their troop strength on the border. The Afghanistan and Cambodia issues would be difficult to deal with, he said.