President Carter yesterday offered Congress an incentive for enacting administration legislation to control hospital costs and trim Social Security benefits, suggesting that money saved by passage of the bills might make it easier to cut Social Security taxes in 1981.

Carter, while not committing himself, made the suggestion in a 50-page written report to Congress outlining his goals and major legislative proposals for the year. There were no surprises in the message, which stressed, as did White House officials who later briefed reporters, that the president's top domestic priority is a package of anti-inflation measures.

Part of that package is the hospital cost containment legislation that Congress refused to enact last year, and which is expected to encounter equally strong opposition this year. A sizable coalition has already formed to oppose the $600 million reduction in Social Security benefits Carter has proposed.

By linking the fates of those two measures to a rollback in Social Security taxes in 1981 -- when a substantial tax increase is scheduled to take effect -- the president clearly hoped to improve their chances of survival.

"If the administration's proposals for Social Security outlay reductions and hospital cost containment legislation are enacted, it would be possible to consider a reduction in Social Security taxes beginning in 1981," he said in the message. "However, such a reduction would have to be considered in light of alternative uses of such savings, including the reduction of any budget deficit and funding of high-priorikty programs."

Earlier this month, administration officials said Carter would consider a cut in Social Securikty taxes beginning in 1981, but without linking it to other legislative proposals.

In addition to the legislative proposals he mentioned Tuesday night in his State of the Union address to Congress, Carter, in the written message:

Said the administration is developing "a comprehensive privacy policy" that in part would deal with the Surpreme Court decision in the Stanford Daily case, which authorized unannounced searches of private property, including news organizations, in connection with criminal investigations.

Called for enactment of several health measures, including a child health assessment program and comprehensive mental health legislation he said the administration is developing.

Said he will propose "overdue changes in the nation's maritime policies," but did not elaborate.

The president also gave no hint in the message of what decisions he is likely to make regarding legislation to begin a national health insurance plan or on the issue of raising domestic oil prices to world levels, which he has promised U.S. allies he will do by 1980.

In the foreign policy section of the message, Carter said he would welcome in the "near future" a meeting with Soviet President Leonid I. Brezhnev to complete the negotiations over a new strategic arms limitation treaty (SALT). Senate approval of a new SALT pact is the administration's top foreign policy goal for the year.

Briefing reporters at the White House, a senior White House official stressed that the president does not believe that Senate consideration of a SALT accord should be "linked" to other Soviet activities around the world.

This was in sharp contrast to comments made last year by national security adviser Zbigniew Brzezinski, who contended that while the administration did not seek it there would be inevitable "linkage" between Soviet behavior and the Senate vote on the SALT pact.

With the Senate SALT debate due to begin as early as the spring, the White House clearly wants to separate the arms accord from other aspects of Soviet-American relations.