Hua Guofeng, whose place at the top of the Chinese leadership has been shaky from the start, faces a political future at least as uncertain as that of the American president he met today in Tokyo for their first official talks.

At 59, still unusually young for a Chinese leader, Hua holds the top positions in the Chinese government, Army and Communist Party. Yet most Chinese and foreigners assume that important decisions are being made not by him but by a group of older leaders ranked just below him. He is where he is because the late chairman Mao Tse-tung anointed Hua as his successor in 1976, a time of political turmoil when Hua's relative inexperience in Peking and provincial background made him a good compromise candidate.

A group of veteran, pragmatic officials led by Vice Chairman Deng Xiaoping took effective control after Mao's death. Hua does not enjoy long-term personal relationships -- the key to Chinese politics -- with that group, but he has cooperated with them as they have brought back the merit system to Chinese education and began to insist that factories make profits.

Now Deng has one of his own proteges, Vice Premier Zhao Ziyang, apparently ready to take over Hua's post as premier. Chinese officials here say they expect Hua to announce at the August meeting of the National People's Congress that he is stepping down to devote more time to his remaining jobs as party chairman and chairman of the military affairs commission.

Chinese and foreign observers would be predicting this turn of events with great confidence if it were not for the fact that Chinese officials similarly predicted that Hua would step down as premier in 1978 in favor of Deng, and that change did not occur. Also, the usually placid Hua appeared quite agitated, but did not answer, when asked by Japanese reporter in May about his plans to step down in favor of Zhao.

To keep his grip on the party chairmanship, which may give him a veto over some of Deng's policies, Hua must bow eventually to demands that he give up the premiership to Zhao. Never in the past have the top party and government jobs been held by the same man, and at the provincial level a concerted effort is being made to have party leaders shed their government titles. Deng himself and two other veteran vice premiers are expected to resign their government positions to make way for Zhao, which would make it all the more difficult for Hua to refuse to step aside.

Still, Hua has in the last few weeks countered the rumors of his shrinking influence with a series of inspection trips to Shanghai, Jiangsu and Liaoning that have been prominently reported in the official press. He also delivered a recent speech before a conference of Army political officers that diverged sharply from Deng's policy of strong support for material incentives in working places.

Until nine years ago, Hua was a little known administrator in Hunan Province with no experience in Peking. Hunan was Mao's home, however, and the chairman was sufficiently impressed with Hua's work and support of Maoist policies to give him a job in the central government. Eventually Hua became public security minister, then premier after the death of Chou En-lai.

Following Mao's death, he helped some members of Deng's group arrest Mao's widow and other Mao disciples and was in turn elected party chairman, but he never appeared to have the full favor of the senior officials allied with Deng.Hua has proved very adept, however, at avoiding the usual pitfalls of leadership in Peking. He has actively resisted special publicity or favors for his wife and family, thus burying memories of the way Mao's wife and family sometimes abused their connections with the chairman. In his several foreign trips, a marked departure from the stay-at-home Mao, he has proved to be a gracious and carefully spoken diplomat, and should prove so again in his meeting with President Carter.