China and the Soviet Union have agreed to sign four new accords on trade and economic, scientific and technological cooperation as both sides moved to tap what one Chinese leader described as "the great potential" for cooperation in these fields, Chinese officials said today.

The accords were announced as visiting Soviet First Deputy Premier Ivan Arkhipov, Moscow's highest ranking envoy to Peking in more than 15 years, wound up formal discussions in the capital with Chinese leaders.

Arkhipov met today with Premier Zhao Ziyang, who called the Soviet official an old friend of China who did much useful work in helping China formulate and implement its first five-year plan, the New China News Agency reported.

However, the agency also quoted Zhao as telling Arkhipov that "really major obstacles" still exist between the two countries politically -- a reference to differences over Afghanistan, Cambodia and the high levels of troops each side maintains at their common frontier. "We hope that the Soviet Union would take some action in solving these problems," Zhao said.

Zhao, however, reiterated China's policy in recent years of separating the development of relations in the nonpolitical field from the political obstacles, the news agency said, and it quoted Zhao as saying that the relatively smooth development of Sino-Soviet economic and trade relations had proved that problems could be solved so long as the two sides take a positive attitude toward them.

"It should not be so difficult" to solve the problems in the political relations between the two countries, Zhao said. "China sincerely hopes that Sino-Soviet relations will truly be improved, and good-neighborly and friendly relations truly established."

The two sides have agreed to sign a five-year, trade agreement by mid-1985, a Chinese Foreign Ministry spokesman said. That agreement, which would run from 1986 through 1990, is likely to boost bilateral trade from about $1 billion this year to $5 billion or $6 billion by 1990, the level of current trade between the United States and China, western diplomats have said.

In addition, the two sides also agreed on the texts of three other accords on economic and technical cooperation, on science and technological cooperation and on establishment of a joint committee in charge of such cooperation, the news agency reported.

These three accords are likely to be signed before Arkhipov leaves Peking Monday to tour the southern cities of Guangzhou and Wuhan and the special economic zone of Shenzen across from Hong Kong, diplomats said. Arkhipov is to return to Moscow on Dec. 29.

Although neither side has provided any details on the content of the agreements, they are expected to include Soviet assistance in upgrading and providing machinery for factories and projects that were built with Soviet assistance in the 1950s.

Arkhipov, who handles economic affairs for the Kremlin and headed the massive Soviet aid program here in the 1950s, is the most senior official to visit China since 1969, when the late premiers Alexei Kosygin and Chou En-lai met briefly at the Peking airport in an attempt to defuse border tensions.

There have been no indications so far that the current visit will provide any breakthrough for substantial improvement of political relations, which have been strained since the two communist giants began their ideological and strategic quarrel nearly a quarter of a century ago.

But the visit has symbolic importance, and it moves toward normalization of relations at a high level. The establishment of a joint economic committee, similar to those China has with other East European countries, adds another structure for dialogue beyond the political consultations that have been held at the level of senior Foreign Ministry officials since 1982 and contacts between foreign ministers, which resumed this year.

Since his arrival Friday, Arkhipov has had three rounds of talks with his Chinese counterpart, Vice Premier Yao Yilin. The four hours of talks took place in a "friendly, mutually understanding and constructive atmosphere" and also touched on "international issues of common concern and bilateral relations," the spokesman said.

Although Arkhipov's reception has been relatively low key, it has been warm, according to some Chinese observers. At the welcoming banquet for him Friday night, for example, Yao addressed Arkhipov as "Comrade Arkhipov," a term the Chinese have not used toward the Soviets for a long time, these observers said.

At a banquet last night, Chinese Vice Premier Wan Li was shown on television embracing Arkhipov not once, but twice.