Secretary of State Cyrus R. Vance, in his first major policy declaration on Asia, committed the Carter administration yesterday to seek full normalization of relations with China but warned that "progress may not be easy or immediately evident."

Vance, who plans a trip to Peking in late August to continue the high-level dialogue begun in the Nixon administration, touched lightly on the Taiwan problem, which has impeded a rapid improvement in relations.

"We acknowledge the view expressed in the [1972] Shanghai communique that there is but one China. We also place importance on the peaceful settlement of the Taiwan question by the Chinese themselves," he said in an address to the Asia Society in New York.

China has refused to renounce the possibility that it will use force to take control of Taiwan, which is bound to the United States by a mutual security treaty. A senior State Department official, conceding yesterday that the Taiwan issue is "the core of the present logjam" between Washington and Peking, said no decisions have been made on the timing or method of solving the problem.

Yesterday's address, billed as a major effort to state the Carter administration's policies to Americans and Asians, broke little new ground and consisted mostly of a broad review of established positions.

The administration's major initiative in Asia to date, the planned withdrawal of U.S. ground forces from South Korea, was justified in language previously used by administration witnesses on Capitol Hill.

Amplifying Vance's statement that the United States will seek to strengthen South Korea's defense capabilities, officials said consideration is being given to upgrading South Korea's antitank weapons, improving its communications, logistics and intelligence capabilities and perhaps leaving behind some of the equipment of the withdrawing U.S. forces.

A study of U.S. military forces in Asia, published yesterday by the Congressional Budget Office, said replacement cost for the equipment of the U.S. infantry division now in Korea could approach $1 billion. The study said reassignment of the U.S. division to NATO-related missions after its withdrawal from Korea would cost an additional $150 million over five years, but that elimination of the unit from the U.S. force structure would save $2.1 billion over the same period.

The CBO study U.S. military forces in Asia appear to considerably exceed the requirements needed to counter the most likely threats in the area. The principal rationale of the U.S. deployments "is now avowedly political," the study said.

"The United States recognizes the importance of its continuing contribution to Asian security. We will maintain a strong military presence in the area," Vance declared in his address. He gave no details.

Vance also said that "the United States is and will remain an Asian and Pacific power."

State Department officials said that discussions with Asian leaders and reports from U.S. embassies made clear the need to repeat at the highest levels of government the continued American commitment to the region in the post-Vietnam-War era.

While praising Japan's democratic institutions and deidcation to peace, Vance gently chided the senior U.S. ally in Asia for not stimulating its economy enough or opening its market sufficiently to foreign goods.

He said there has been "some progress" toward overcoming the residue of bitterness between the United States and Vietnam, and called for establishment of normal relations. But he reiterated the U.S. rejection of the aid payments that Vietnam says it was promised by then-President Nixon. "We cannot accept an interpretation of the past that imposes unfounded obligations on us," Vance said.