U.S. Defense Secretary Harold Brown and Chinese Vice President Deng Xiaoping appeared to agree today to cooperate in countering Soviet moves in Afghanistan, with the U.S. signaling the new relationship by endorsing sale to China of a sophisticated satellite ground station not available to Moscow.

U.S. officials indicated by approving sale of the Landsat ground station, which has some military capabilities, that they had abandoned the old effort to treat China and the Soviet Union evenhandedly.

During their 2 1/4-hour meeting this morning in the Great Hall of the People, Deng told Brown that "all countries in the world should enter into an alliance to deal seriously with [Soviet] global expansionism," the official New China News Agency said.

It said Brown told Deng, "The United States and China should coordinate their policies in the face of the threat from the Soviet Union," particularly after its invasion of Afghanistan.

Deng replied that "China and the United States should do something in a down-to-earth way so as to defend world peace against Soviet hegemonism."

Defense Department spokesman Thomas B. Ross later confirmed the Chinese report of Deng's and Brown's comments at the meeting. A U.S. officials said details of any joint action would not be released before a scheduled Brown press conference here Wednesday. He also indicated that final agreements might not be reached until after the Brown trip.

The Chinese have made no secret of their need for better weapons. But according to a U.S. official, they have made no request for such weapons during these talks. He said this was in recognition of the firm U.S. policy against such sales to China.

Instead, at a banquet tonight, the Chinese Defense Ministry's director of foreign affairs, Chai Chengwen, spoke of "expanding contacts between military personnel" of the United States and China.

Ross announced the U.S. decision to allow sale of "a ground station capable of receiving information from the U.S. earth resources satellite known as Landsat." The satellite has heat-sensing equipment that provides information useful in developing agriculture and exploring for oil, gas and minerals.

If the sale is approved by the U.S. Congress and a special committee formed by NATO, China will join 20 other countries who have such ground stations. A U.S. official said the data transmitted by the satellite would have little military application because transmissions are controlled by U.S. technicians. Nevertheless, the computers and taping systems in the ground station itself could be used for military purposes.

Ross said that China agreed, however, not to divert the equipment to other uses. A new, high-technology Landsat satellite is scheduled for launch in 1981.

A U.S. official declined to say if Brown and Deng discussed the reported Sino-American interest in working together to increase shipments of arms of Pakistan, threatened by the Soviet invasion of neighboring Afghanistan. He also declined to say if the two sides discussed supplying arms to Moslem insurgents fighting the Soviet troops and the new Soviet-backed government in Afghanistan.

[Chinese Premier Hua Guofeng today said, "the Soviet Union's armed invasion of Afghanistan now constitutes direct agression and the occupation of a nonaligned Islamic country to the Third World. Any excuses offered by the Soviet Union about the event are pointless," according to a new China News Agency account transmitted by Reuter.]

An American official said Deng had expressed interest in a stronger U.S. defense and had been told by Brown that the U.S. defense budget was being increased. He said Brown told Deng that Washington was augmenting its ability to send forces great distances quickly, and that the situation in Iran and Afghanistan had "crystalized U.S. public opinion behind President Carter in supporting such actions."

According to the Chinese news agency, Deng told Brown he "hoped the United States would strengthen its unity with Western Europe." Brown repeated to Deng the NATO agreement to increase defense spending by 3 percent in real terms annually and to modernize its tactical nuclear force.

At the banquet tonight for reporters covering the Brown visit, Chinese Army Deputy Chief of Staff Wu Xiuquan was asked to explain what Deng meant by "down-to-earth" joint action to counter Soviet expansion. Wu cited the recent Sino-Japanese friendship treaty and the normalization of U.S.-Chinese relations a year ago as down-to-earth actions but would not be more specific.

During the banquet, however, Wu joined in a series of enthusiastic toasts that ended with choruses of "down to earth, bottoms up," in Chinese and English.

Wu also said: "It is no use to talk empty words against hegemonism," China's code word for Soviet efforts to control other countries. "It is also useless to depend on some declarations."

This afternoon, Brown visited the Chinese military college, which trains mostly middle and upper-level Army officers. Commandant Xiao Ke, a veteran of the Chinese Communist Army's long march of the mid-1930s, gave Brown a quick lecture on what he said were Soviet intentions to use Southwest Asia to gain a route to the Indian Ocean. "The only way to deal with Soviet aggression is for all the world's people to rise in resistance," Xiao said.

Brown was shown a number of exhibit halls in the academy, displaying models of tanks, jet fighters and other equipment that the chinese conducting the tour admitted were out-of-date.