A divided Reagan administration is studying the new Soviet proposal in the Geneva arms negotiations and is not likely to formulate a clear-cut response before the current round of talks is over on June 26, official sources said yesterday.

The officials said that ambiguity and complexity in the Soviet bid, which was described in general terms Monday by Soviet leader Mikhail Gorbachev, make a quick U.S. response difficult. Already disagreement is emerging within the U.S. administration between those who see little movement or merit in the new proposal, and those who believe it may offer at least the basis for fruitful negotiations.

Illustrative of the differences are the varying interpretations different officials give to the new Soviet proposals on research dealing with space-based missile defense, including President Reagan's Strategic Defense Initiative.

One administration official said the Soviets continue to insist that any research "for the purpose of" creating an SDI system would be banned under the new Soviet position, as in their previous stands. Another official was quoted as telling members of Congress that research on SDI would be permitted, but that hardware demonstrations of SDI components would be banned. Still another official said the offer is so ambiguous it is difficult to be sure which interpretation is correct.

Gorbachev, in his address to the Central Committee of the Soviet Communist Party, said that under the Soviet proposal, "work in the field of the SDI is limited to the level of laboratory research -- that is the threshold that the United States has already actually approached."

Secretary of Defense Caspar W. Weinberger said yesterday that the Soviets' purpose in making the new proposal was "to define SDI out of existence," the Los Angeles Times reported.

Reagan may give at least a hint of his own attitude on Thursday when he speaks at a high school graduation in Glassboro, N.J., the site of the June 1967 meetings between President Lyndon B. Johnson and Soviet Premier Alexei Kosygin. A White House official said Reagan plans to discuss Soviet-American relations and arms control in a speech intended to "get the summit process back on track."

In Geneva last November, Reagan and Gorbachev agreed to meet sometime in 1986 and again in 1987, but since then plans for future summits have foundered.

The Soviet proposal and the administration discussions come amid strong criticism here and among U.S. allies of Reagan's decision to abandon compliance with the limits of the unratified 1979 Strategic Arms Limitation Treaty II. A House resolution asking Reagan to reverse his SALT II decision is expected to be passed this week, with a similar measure in the Senate.

Democratic sources on Capitol Hill said they believe the Soviets are moving toward a more reasonable position, and expressed hope for a positive response from the administration.

In the new offer, as portrayed in Gorbachev's address and by Washington officials, the Soviets propose to reduce the strategic nuclear arsenals on each side to 1,600 ballistic missiles, bombers and long-range cruise missiles, and to limit the number of "nuclear charges" (bombs or warheads) they could contain to 8,000 on each side.

The Soviets would limit the number of "nuclear charges" on land-based missiles to 60 percent of the overall total as measured in warheads -- in this case, 4,800, officials said. This provision is important because it is among those that would cause actual cutbacks in major Soviet weapons if adopted. An earlier Soviet proposal would have limited each side to 6,000 charges, with a maximum of 3,600 being allocated to land-based missiles.

The existing U.S. proposal, first broached last November, is for a limit of 6,000 strategic missile warheads, with a maximum of 4,500 on land- and submarine-launched missiles. The U.S. also proposed a limit on total ballistic missiles and bombers of 1,800. Some of these limits are close to those now being proposed by the Soviets.

In another change, the Soviets dropped their insistence that submarine-launched long-range cruise missiles be banned, but they continue to bar long-range cruise missiles on surface ships. The new Soviet proposal drops the demand that U.S. nuclear-capable fighter planes and carrier aircraft within range of the Soviet Union be counted as strategic weapons, saying these will be considered intermediate-range arms.

In the area of space defense, Gorbachev said the Soviets propose "nonwithdrawal . . . at least in the course of 15 years" from the 1972 Anti-Ballistic Missile Treaty. The ABM Treaty now stipulates that either side may withdraw from the treaty at six months' notice.

The U.S. position has been that the ABM treaty does not limit SDI research and that tests planned through at least 1989 will remain within the limits of the treaty.

The reductions in strategic offensive arms proposed by the Soviets would be contingent on U.S. agreement to limitations in space defense. This continues to be a central barrier to progress, in the view of U.S. officials who are prepared to move ahead in the negotiations.