Chinese Foreign Minister Huang Hua's recent trip to Zaire has underlined the extraordinary importance of Africa to Peking's foreign policy, without signalling any significant increase in the flow of Chinese economic or military aid to that continent.

Huang's visit also demonstrates Peking's willingness to cooperate with Western moves against Soviet and Cuban influence in Africa. It is one of a number of gestres, like the visit of Chinese reporters to the U.S. nuclear aircraft carrier Enterprise in Hong Kong harbor Tuesday, that signal China's approval of American military muscle in certain parts of the world without Peking actually saying anything.

Despite Huang's tour of embattled Zaire, there has been no sign so far that China is willing to go any further than what has been mostly a war of worlds against the Soviets in Africa coupled with what is by Chinese standards a substantial amount of economic aid.

"As Zaire occupies an important position in the heart of Africa, Soviet social-imperialism and its agent want to gain control over Zaire," Huang said in Kinshasa. "This is part of the Soviet global strategy for world hegemony."

It was the sort of statement that has been repeated almost daily in the offical Chinese press ad at a steady stream of banquets for visiting Africa dignitaries in the 1970s.

Since 1970, about 30 African nations havereceived at estimated total of $2 billion in Chinese foreign aid. Chinese military advisers and arms have been provided to Africa guerrilas in Angola, Mozambique and Congo (Brazzaville), as well as to black nationalists fighting for black majority governments in Rhodesia.

Peking has been drawn to the African continent to bolster its credentials as a leader of the revolutionary, under-developed world. It has also been moved by the susceptibility of several African nations to influence from Moscow, its arch-foe.

Africian states have, in turn, tried to get whatever they could from both Peking and Moscow, and occasionally gritted their teeth at the annoying by-products of the Sino-Soviet rivalry. They have expressed exasperation, for instance, at the refusal of a Chinese medical team to work in the same town as a Soviet team.

Yet, several nations have appreciated the Chinese contribution. Mozambique President Samora Machel told a Peking banquet last month that Chinese military aid "constituted one of the factors of vital significance in our victory over Portuguese colonialism."

That revolutionary tradition remains key to the Chinese presence in Africa no matter how hopeful American policymakers might be of Chinese assistance in stopping the Soviets. Peking has given approving notice lately to America nefforts to stymie Moscow in the Horn of Africa, Zaire and Angola.

The New China News agency credited The Washington Post with exposing sudden Soviet purchases of cobalt early this year as evidence of Soviet involvement in plans of the invasion of Zaire's cobalt-producing Shaba Province.

White House national security adviser Zbigniew Brzezkiski reportedly briefed the Chinese in detail on U.S. Africa policy during his Peking visit last month. Some observers here suggested Huang's sudden trip to Zaire may have been partly at American urging.

Yet diplomatic analysts doubt the Chinese can, or are willing, to help Washington in its most vital African policy goal: Preventing a full-scale conflict in Rhodesia that could end with a pro-Soviet government in power. It seems too much to ask the Chinese to pressure their own Rhodesian guerrilla clients into accepting a peaceful compromise with whites and black moderates.

Nor do the Chinese seem interested now in matching their huge investment of rhetoric with an equal amount of new financial aid to African states, particularly after the disappointments attached to Peking's foreign aid flagship, the $400 million, 1,200-mile Tanzania-to-Zambia railroad that opened two years ago.

The Chinese loaned the money for the project and assigned 15,000 technicians and workmen to build it, but Tanzanian President Julius Nyerere continued cooperation with Moscow and has been indirectly criticized China's position on Zaire in recent weeks.

Peking appears to have shied away from any other projects of that magnitude, particularly since it has announced its crash program to develop its own domestic economy. The Chinese have limited themselves mostly to health clinics and smaller loans for road improvements and rice-growing projects.

The Chinese have tried to win friends with lavish and frequent receptions in Peking for even the most minor of African states. New Communist Party Chairman Hua Kuo-Feng is often at the airport to welcome African heads of state. Even vice Chairman Teng Hsiao-ping, has begun to join in the African welcomes after months of showing little interest in the continent.

The number of African visitors to Peking seems to rise and fall with the amount of political turmoil in China. Peking officials seem most receptive when they have no internal squabbles on their minds. In the troublesome year of 1976, five major African delegations visted. That climbed to eight last year as the new government in Peking began to assert itself.

In other developments in China, an official broadcast monitored here revealed that the mayor of Tienstsin, China's third largest city, has been removed from office. Mayor Hsieh Hsueh-kung was thought to have been on shaky ground because of links to a radical group purged in 1976. He was replaced by Lin Hu-chia, a former Chekiang provincial official who had been purged during the Cultural Revolution of the 1960s.

Also, a newpaper here with links to Peking reported yesterday that the Soviet navy was now operating freely out of Vietnam's Camranh Bay, a former U.S. base, and building another naval base on Dao Cat Ba island near Haiphong.