The abrupt postponement of a top Soviet official's visit to China raises far-reaching questions about Moscow's policy toward Peking. The announcement caught Chinese officials by surprise, as it did diplomats and other observers here.
Ivan V. Arkhipov, Soviet first deputy premier for foreign economic relations, would have been the highest-level Soviet official to come to China since 1969. His long-planned visit, scheduled to begin May 10, was expected to include extensive talks about Soviet economic cooperation with China.
Diplomats here say the move raises several questions:
* Is Moscow warning Peking, in the wake of President Reagan's successful visit, that China's ''independent foreign policy'' has shifted too far in Washington's favor?
* Or is the Soviet Union reevaluating its whole foreign policy? Other evidence for such a reevaluation is Moscow's decision not to compete in the Los Angeles Summer Olympics.
One possible reason for postponing the Arkhipov visit could be renewed hostility on China's southern border with Vietnam, an ally of the Soviet Union. What role such events may have played in Moscow's decision is unclear.
But so far the Chinese have decided to take the announcement in stride and are withholding judgment on Moscow's immediate or long-term intentions.
According to Chinese Foreign Ministry spokesman Qi Huaiyuan, the Soviets said they ''were not fully prepared.'' However, Arkhipov's visit had been in the works for some months and was publicly announced in February this year. So far the Chinese government has refused to speculate about the Soviet decision.
''We think they have their reasons why they needed to tell us only at the last moment,'' said one top Chinese official. ''We don't feel angry, nor do we feel happy. Since they need more time to make preparations, we agree to that. . . .''
The timing of the Arkhipov trip had been widely interpreted as a counterbalance to China's warmer relations with the United States, since it was scheduled only 10 days after President Reagan left Shanghai. The proposal for a high-level Soviet official visit to China was discussed at the third round of Sino-Soviet talks last October.