The Chinese government has agreed to broadcast a Peking University speech Monday by Vice President Mondale to the entire country, apparently the first time since at least the 1950s that a foreign leader has been allowed to address the world's most populous nation.

Administration officials traveling with Mondale said the Chinese arrangements for the speech at the historic university indicated a very healthy state of relations between the two countries. They also said both sides will sign an agreement Tuesday on a new series of cultural exchanges.

Asked about reports of Chinese unhappiness with delays in U.S. trade benefits for Peking, Mondale's aides said the Chinese had not raised the issue yet in their informal talks with the vice president. Trade issues will come up in Mondale's formal talks with Vice Premier Deng Xiaoping beginning Monday morning.

Mondale's aides indicated that the trade agreement bill in Congress, which includes most-favored-nation tariff benefits for China, could be delayed until the end of the year by the logjam of legislation. A Chinese official at tonight's welcoming banquet for Mondale in the Great Hall of the People confirmed that Peking was unhappy about the delay, despite the explanation.

Officials traveling with Mondale did not reveal the contents of his university speech, to be delivered to students and teachers at 3:40 p.m. Monday. It will be recorded by the Chinese and broadcast, with Chinese-language voiceover, on television in all large cities later in the day, U.S. officials said. They said they expected that a radio broadcast of the speech, which would reach most rural areas, also would be made.

Peking University, considered by many the country's premier institution of learning even before the victory in 1949, provides a prestigious forum that has not heard an official U.S. speaker in 30 years. The Chinese said they did not know when the last foreign leader addressed the whole country, but said there had not been one since the 1950s, when Soviet leaders made well-publicized visits here.

At tonight's banquet, Mondale was joined by three members of the ruling Communist Party Politburo: Vice Premiers Deng, Yu Qiuli and Geng Biao, as well as Foreign Minister Huang Hua. The Chinese also announced well in advance that Mondale would be meeting later in the week with Party Chairman Hua Guofeng, rather than keeping Hua's schedule in doubt as they have during past visits by U.S. officials.

"If we strengthen our bilateral ties, we can both make dramatic economic progress, we can both enrich our cultures," Mondale said in his toast at tonight's banquet.

"But above all," he added, "an enduring Sino-American relationship will promote the stable international environment we both need to meet our domestic challenges and address problems of global concern."

In his toast, Deng told Mondale, "I still remember clearly many of the moving scenes" of his visit to the United States. "There is wide scope for economic cooperation between China and the United States," he said.

Perhaps as a reminder of Chinese impatience on the trade issue, however, Deng added that relations will improve steadily "so long as the two sides. . .deal with the concrete issues between China and the United States on a basis of equality and mutual benefit."

Administration officials said the new rounds of exchanges negotiated with the Chinese included a Chinese cultural delegation to the United States led by Culture Minister and former ambassador to Washington Huang Zhen.

China also is scheduled to send cinema and art delegations, the United States would send a dance troupe and paintings to China, and each would have a week-long film festival in the other's country.

Earlier today, Mondale visited a market area while huge crowds gathered to watch him buy a half pound of onions.