Sino-American diplomatic ties, an international link of great but uncharted potential, were inaugurated here last night to anti-Soviet rhetoric from the Chinese side and suggestions of patience from the United States.

Several Hundred present and past American officials and their spouses, headed by Vice President Mondale, Secretary of State Cyrus R. Vance and presidential assistant Zbigniew Brzezinski, celebrated the new relationship at a reception given by the People's Republic of China at its embassy -- until yesterday its quasi-offical liaison office -- at the site of a former hotel on Connecticut Avenue.

Ambassador Chai Tse-min, China's senior diplomat in Washington, spoke enthusiastically of the "historic significance" of the new relationship. He declared that the tie "will certainly play an active role in combating the expansion and aggression of hegemonism," Peking's code word for its communist arch-rival, the Soviet Union.

Mondale, in reply, spoke of the bilateral gains of commerce, tourism and exchange and said nothing of an anti-Soviet alliance. He cautioned that sentiment alone cannot bridge the gap of ideology and culture between China and the United States but said that "parallel interests in creating a world of economic progress, stability and peace" had brought the two nations together.

The vice president, in the unusual position of counseling forbearance to a people traditionally noted for patience and sophistication, said that "this new relationship to be successful will require patience, wisdon and understanding."

He also declared that "equality and realism" should be the touchstones of the new chapter for the two nations to work together, "with a realistic sense of our interests at stake."

Beyond the enthusiastic handclasps and champagne toasts, the inference was plain that the United States seeks to avoid an emotional embrace with Peking that could generate concern in Asia and bring new trouble from the apprehensive Soviets. China, for its part, appears unconcdrned about side effects of an alliance with Washington.

President Carter, who was returning yesterday from the presidential retreat at Camp David, Md., did not attend the diplomatic reception. Several Cavinet members and high State Department officials were present, along with members of Congress, leaders of private organizations on U.S.-China affairs, and journalists.

Former secretary of state William P. Gogers, who presided over the mostly uniformed State Department when Henry A. Kissinger made his sensational and secret trip to China in mid-1971, was present. Kissinger was not.

Chai, who will be accorded the full rank of ambassador when the envoys of the two sides are officially accredited on March 1, was careful to credit former presidents Richard M. Nixon and Gerald R. Ford as well as Carter for their efforts which brought normalization of relations to fruition.

The Chinese also arranged to give nearly equal prominence in their statements and the placement of their guests to Vance and Brzezinski, who have been at odds on some matters of policy. Vance has been the chief U.S. negotiator with the Soviets, with Brzezinski playing a larger role in the Establishment of relations with China.

The secretary of state and the White House national security adviser stood on a platform behind Chai and Mondale during the diplomatic toasts. The top officials were backed by large Chinese and American flags, with the field of stars in the U.S. flag mistakenly placed in the upper right corner.

Chai spoke expectantly of the forthcoming visit to Washington of Vice Premier Teng Hsiao-ping, the architect of normalization on the Chinese side, who is believed to be the leading figure in Chinese decision-making at the present time. The diplomat said Teng's visit, which is scheduled to begin Jan. 29, "will be another major political move in international affairs."

At an earlier reception sponsored by the National Association of Chinese Americans, Chai declared that the new Washington-Peking link will be "a severe and heavy blow to those couontries and groupings which attempt hegemonism, whether it be global or regional."

In keeping with the counciliatory nature of recent statements and actions regarding Taiwan, Chai expressed hope that "the Taiwan authorities" will decide to "go with the tide" and make "positive efforts for reunification." He forecast that someday "Taiwan will come to the embrace of the motherland."

Several hundred pro-Taiwan Chinese demonstrated in a light rain across the street from the White House yesterday afternoon. They marched a half-mile from Chinatown behind Nationalist flags chanting "Keep China Free."

Police kept the protesters in Lafayette Park. About two dozen sympathizers were allowed to march in front of the White House gate. The demonstators, who included Caucasians, carried signs that read "No Human Rights in China." Another placard read "Mao killed more Christians than Hitler killed Jews."

Some of the Chinese said they had come to the capital from surrounding states. They carried a petition to Carter that quoted from a statement he made in Kansas City in October 1976 while running for the presidency: "I wouldn't go back on the commitment that we have had to assure that Taiwan is protected from military take-over."

The former Windsor Park Hotel, a 400-room building where the Chinese reception was held last night, still bears the legend, "Liaison Office of the People's Republic of China." According to State Department legal adviser Herbert J. Hansell, who was among the guests at the reception, the United States now considers it the Chinese embassy.