Chinese Communist Party leader Hu Yaobang has postponed a visit to the United States originally expected for this year, foreign diplomats said this week.

The reason for the postponement, according to these diplomats, is that Hu is already committed to making a trip to four West European nations in May and June. It would be unusual for him to make two major trips abroad in the same year, the diplomats said.

No dates for a trip by Hu to the United States had been set. President Reagan invited Hu during Reagan's visit to China in April 1984.

One diplomat speculated that Hu might be reluctant to visit the United States at any time close to a visit to Washington by Soviet leader Mikhail Gorbachev because it might overshadow Hu's trip.

High-level exchanges of visits between Peking and Washington have become part of an annual pattern in Sino-U.S. relations.

In Washington, State Department officials confirmed Friday that Hu's visit had been postponed. They said discussions are under way to substitute a visit this year by another Chinese official, such as Hu Qili, who is being groomed to take over the party leadership after Hu Yaobang; Vice Premier Tian Jiyun; or Vice Premier Yao Yilin.

[The most likely dates for such a visit would be May, after Reagan returns from the Tokyo economic summit hosted by Japanese Prime Minister Yasuhiro Nakasone, or in the fall, officials said.]

In another development, delegates to an international conference here said Deng Pufang, who heads China's organization for the disabled and is a son of China's top leader Deng Xiaoping, will travel to the United States in early May to look at rehabilitation facilities.

Conference delegates said the trip to the United States would be a "working visit" focused on rehabilitation services. But they added that given Deng's relationship with China's top leader, his visit was also likely to have political overtones. One delegate, who asked not to be named, said that a Washington meeting with Reagan was likely to be arranged. The delegate said that Deng Pufang's visit would strengthen the relationship between the United States and China.

Deng's visit is being sponsored by the National Committee on U.S.-China Relations in New York, which invited him more than a year ago. Committee vice president Jan Berris said the visit is likely to be for three weeks and will include several days in Washington and possibly trips to New York, Orlando and Indianapolis.

Little was known about Deng until 1984, when he disclosed in an interview with a French magazine that Red Guards had pushed him out of a fourth-story window in 1968 during the Cultural Revolution. The fall broke his spine and left him paralyzed. His father was labeled a "capitalist roader" and purged from office.

The younger Deng delivered an opening address here this week to the First International Conference on Rehabilitation of the Handicapped in China.