The United States has proposed a series of interim solutions in the Geneva negotiations on medium-range missiles in Europe in recent weeks but the Soviet Union has firmly rebuffed such offers, according to a senior Reagan administration official close to the talks.

He said the United States is negotiating in "utmost seriousness" to achieve a compromise before the first batch of Pershing II and cruise missiles is to be deployed in Western Europe this December. A draft treaty text accompanied by suggestions on various levels of warheads to be deployed by both sides, ranging from zero to 450, has been submitted to Soviet negotiators.

But the Soviets have been more intransigent in spurning these interim proposals, tabled since the current talks resumed May 17, than in previous rounds when they rejected President Reagan's zero-zero solution as "a boulder blocking the stream of progress," the senior official said.

That plan, proposed by Reagan in November 1981, offered to cancel western deployment of 572 cruise and Pershing II missiles if the Soviets dismantled their entire arsenal of medium-range rockets. Last March, Reagan signaled greater flexibility by proposing an interim solution of limited deployment levels to be worked out in Geneva by chief U.S. negotiator Paul H. Nitze, who visited Bonn today for a symposium on western security issues sponsored by West Germany's Social Democratic Party.

Leading Social Democrats have urged the United States to show even more flexibility by publicly espousing the so-called "walk in the woods" formula tentatively agreed to last July by Nitze and Yuli Kvitsinsky, his Soviet counterpart.

During an informal outing, the two men conceived a package that would cut Soviet SS20s aimed at Europe to 75. The United States would deploy 75 cruise missile launchers but no Pershing II rockets. The formula was subsequently rejected in Washington and Moscow.

The senior administration official contended that if the United States now embraced such an arrangement, it would be seized on by the Soviet Union not as a final agreement but as a new U.S. position for further haggling.

Any ultimate agreement, he predicted, would then emerge only as a compromise between the "walk in the woods" formula and the present Soviet posture, which still refuses to concede any deployment of the new U.S.-built missiles.

While some Europeans think adopting the "walk in the woods" line may assuage public opinion, the net effect would undermine or put at risk the western negotiating position, the U.S. official said.

Unlike the "walk in the woods" formula, he said, all of the recent U.S. proposals have involved some mix of Pershing II and cruise deployment. They also appear to mark the first time the United States has advanced proposals in the talks based on counts of warheads rather than missiles.

The Soviets, meanwhile, have not offered any new concessions except "the same deal, better packaged" since the early stages of the negotiations.

Moscow has offered to cut its force of 351 SS20 missiles back to 162, or the equivalent of French and British missiles now deployed, if the West renounces any stationing of cruise and Pershing II rockets.

The Soviets' insistence on counting French and British systems represents a blatant attempt to split the alliance and has become the most intractable issue in the Geneva talks, the senior official said.

The West rejects the notion of including the French and British missiles in the negotiations because they are deterrent forces of third countries and consist mainly of submarine-launched missiles matched by similar Soviet systems.

"The choice is before Moscow now," the senior official said, noting that there have been no signs of cracks in the Soviet position. "We hope they will realize that time is slipping by and provide some indications of doing something."

In adopting a more truculent stance recently, the Soviets have stressed that if French and British systems are upgraded in the next decade to more than 1,200 warheads, they would "feel entitled" to target as many as 400 triple-warhead SS20s on Europe, with no limits on such missiles aimed at Asia, the U.S. official said.

The extreme mobility of the SS20s also poses a serious problem, as Moscow has stiffened demands for complete freedom to transfer such systems between European and Asian sites within the Soviet Union.

A negotiated agreement that "alleviates security problems in Europe and transfers the burden to Asia is hardly what we are striving for," the senior official said.

The Soviets have also sought what he termed "radical controls" on aircraft delivery systems, where the United States is said to hold a decided edge.