Vice President Bush said today that the United States would welcome improved ties between China and the Soviet Union leading to reduced tensions and a resolution of regional conflicts. But Bush said he doubted that the two Communist nations would ever reach anything approaching their former alliance.

Bush said the United States had an interest in seeing a resolution to the three major issues now dividing China and the Soviet Union: Soviet troops on the Chinese border, the Soviet occupation of Afghanistan and Moscow's support for the Vietnamese occupation of Cambodia.

"As things improve, there's something in that for everybody," Bush said at a press conference here at the conclusion of a six-day visit to China.

In response to a question, Bush said a return to the close relationship that existed between the two Communist giants during the 1950s would be "simply unthinkable." Bush said the Chinese were pursuing an economic policy of "incentive and investment and opportunity that contradicts the path the Soviets are on."

"I'd like to see the Soviets do some of that, because I think it would be a moderating force on their external behavior," said Bush, referring to the possibility of the Soviets following the Chinese example in economic policy.

Bush's statements appeared to be the first time such a high-ranking administration official has welcomed the possibility of improved relations between Moscow and Peking. Reporters asked Bush several times during his stay in China to comment on Sino-Soviet relations.

The Chinese and Soviets concluded a major trade agreement this summer. During the past few years, they have been improving ties in a variety of fields. During Bush's visit, half a dozen Soviet delegations were visiting China. The two sides recently agreed to exchange visits by foreign ministers for the first time in more than two decades.