The Carter administration has decided to push toward resumption of U.S. trade and tariff benefits for the Soviet Union and has launched a diplomatic initiative aimed at taking action by the time of next month's summit meeting, administration officials said yesterday.

The Carter plan, according to these sources was put to Soviet Ambassador Anatoliy F. Dobrynin in a meeting late last month by Secretary of State Cyrus R. Vance and Secretary of the Treasury W. Michael Blumenthal.

A renewal of trade benefits for the Soviets would be controversial in Congress, which in 1974 tied U.S. economic advantages to emigration policy in the case of comunist countries. Some lawmakers say they believe that recent Soviet performance in permitting stepped-up emigration of Soviet Jews justifies a resumption of trade benefits, but some other lawmakers insist that it does not.

Another factor is the Carter administration's desire to grant the trade and tariff benefits of "most-favored-nation" status to the People's Republic of China. President Carter has made plain his wish to move ahead in parallel steps, so far as possible, with the two rival centers of international communism, the Soviet Union and China.

Ever since the decision to normalize diplomatic relations with China last December, high administration officials have been considering whether, how and when to move ahead with both Moscow and Peking.

The discussions have been given urgency by the movement toward a U.S.-Chinese trade agreement, the U.S.-Soviet agreement on basic terms of a new strategic arms treaty and the June 15 Vienna summit meeting of Carter and Soviet President Leonid I. Brezhnev to sign the SALT II treaty and launch a new stage in Washington-Moscow relations.

Under the terms of the 1974 law, cosponsored by Sen. Henry M. Jackson (D-Wash.) and Rep. Charles A. Vanik (D-Ohio), the president can grant trade benefits for one year if he receives "assurances" that policies of the nation concerned will in the future "lead substantially" to freer emigration. The presidential action is subject to congressional review.

Some State Department lawyers are reported to have expressed the view that the "assurances" must be in writing. Other State Department and Justice Department lawyers are reported to disagree, saying that the assurances can be in another form.

Experts on Soviet affairs have expressed doubt that the Soviets would provide written assurances about their emigration policies, which they consider to be their internal affairs.

State Department sources said yesterday that on April 27, Vance and Blumenthal sought a way around the problem in a meeting with Soviet Ambassador Dobrynin.

Vance and Blumenthal stated, according to the sources, the U.S. "understanding" that certain current Soviet emigration practices have become the norm and are expected to be continued. If Moscow will accept this Washington will consider the transaction to be the necessary assurances under the Jackson-Vanik law.