President Reagan expressed his approval yesterday that the Soviet Union, for the first time in his administration, has put forth a comprehensive proposal for reducing nuclear arms, and said he "is hopeful that this would provide a basis for discussion."

Reagan's comments, in a briefing for Republican congressional leaders, came as chief U.S. arms negotiator Max M. Kampelman flew home from Geneva and prepared to brief senior administration officials on the new Soviet proposal, which was presented Monday and Tuesday in the Geneva negotiations.

White House spokesman Larry Speakes said that Reagan told Soviet Foreign Minister Eduard Shevardnadze at the White House last Friday to carry the message back to Moscow that "we are not playing games with arms control -- the United States means business," and that "the United States is not seeking superiority, but we will not let any other nation have superiority."

Speakes made the comments in reporting the president's remarks in a closed meeting with Senate and House GOP leaders.

One of the lawmakers quoted White House National Security Adviser Robert C. McFarlane as saying that Reagan's meeting with Shevardnadze was "the most useful meeting" with the Soviets in 15 years.

McFarlane reported on the meeting to British Prime Minister Margaret Thatcher and French President Francois Mitterrand in a secret trip last weekend to London and Paris, the White House announced.

McFarlane was quoted as telling lawmakers yesterday that the Soviet offer, which includes a proposal for a 50 percent cutback in certain offensive warheads and bombs Moscow deems strategic, was a combination of old and new ideas, "some of which moved the ideas forward."

A State Department official familiar with details of the still-unfolding Soviet plan said "there is no way to get an agreement" by the two nuclear superpowers by the time of the Nov. 19-20 summit meeting of Reagan and Soviet leader Mikhail Gorbachev in Geneva.

"What the two leaders could do is to point us in a direction for progress in succeeding rounds" of the arms negotations following the Geneva summit, the official said.

Among the criteria being used within the administration to evaluate the Soviet offer, this official said, are: how it will affect "strategic stability," especially the deployment of large Soviet SS18 missiles; how the offer would affect the future of Reagan's Strategic Defense Initiative, or "Star Wars" plan; how the plan would affect U.S. ability to back up NATO's conventional forces in Europe, and how the proposed cutbacks would be verified.

The official said it was clear that the United States would not accept any plan that permits the Soviet Union on its side to compensate for British and French nuclear forces.

U.S. and Soviet negotiators argued about this point without reaching an agreement in the 1981-83 Euromissile negotiations. The Soviets are reported to have reintroduced a demand for such compensation in their new proposals, presented this week.

Before leaving Geneva, where U.S. and Soviet negotiators met behind closed doors for the third straight day, Kampelman told reporters that the Soviet proposals are "very complex and very conditioned."

"It is important to pay close attention to the fine print," he said.

Washington officials said that Kampelman returned for essentially "personal reasons" but is likely to brief top officials on the Soviet proposal, probably including Reagan.