The Reagan administration is expected to propose that the United States and the Soviet Union negotiate reductions to the lowest possible level in planned or existing intermediate-range, nuclear-tipped missiles based in Europe, perhaps even leading to elimination of such weapons, government sources say.

This is emerging as a central factor in the administration's preparations for talks with Moscow on these so-called Theater Nuclear Forces (TNF) which are scheduled to begin Nov. 30 in Geneva.

The idea of pursuing substantial reductions or even eliminating these weapons is one that U.S. allies in Europe, facing strong political pressures at home to make progress in arms control rather than just rearmament, have been pressing the United States to accept.

Until recently, the administration seemed skeptical of the European approach, fearing it might undermine support for going ahead with deployment of TNF weapons while negotiations get under way. Now there appears to be greater acceptance of European political needs plus agreement here that a deep-cut proposal would require greater reductions from the Soviets than from the United States.

The likely plan involves this potential tradeoff: the United States would propose to reduce substantially or even forgo deployment of the 572 nuclear-tipped Pershing II missiles and cruise missiles to be installed in Western Europe beginning late in 1983 if the Soviets would remove all or substantial numbers of their new SS20 missiles and older SS4 and SS5 intermediate-range missiles already deployed in the Soviet Union and capable of striking Western Europe.

Government officials stress that no final decisions have been made on the opening U.S. position or how this idea of major reductions will be expressed. Those decisions will be reviewed in coming weeks at a top-level National Security Council meeting here and with allies at a meeting of the special consultative group within NATO at Brussels.

But several specialists say the so-called "zero-level option," which would mean removal of all such missiles on both sides, or something close to it in the way of substantial reductions "to the lowest possible level," is likely to be part of the initial American proposal.

Such an approach would also be in keeping philosophically with the way the Reagan administration is developing its position on possible future arms talks with Moscow dealing with the big, intercontinental-range strategic weapons--bombers and land-based and submarine-based missiles--of the United States and the Soviet Union. President Reagan has also called for major reductions rather than just limitations in those talks.

Those talks have previously been known as SALT, for strategic arms limitation talks. But now the Reagan administration, to stress the commitment to reductions, frequently refers to them as START, for strategic arms reduction talks.

Similarly, officials say the TNF talks on European-based missiles are increasingly being referred to as the Intermediate-range Nuclear Force (INF) talks.

Sources say this still unofficial shift also reflects a change long sought by Europeans, especially West German Chancellor Helmut Schmidt. The Europeans feel the TNF designation simply added to the impression in public that Europe was somehow a separate atomic battlefield for the two superpowers.

Officials say it is not yet decided what the definition of "intermediate" will be but that it will probably include missiles able to fly between 1,000 and 5,500 kilometers, equivalent to 600 to 3,300 miles.

The American view is that the talks initially should focus on the key missile systems of both sides, and that all SS20s be included because they are mobile and even those closer to Asia than Europe could be moved. The United States also will insist, officials say, on equal ceilings, adequate verification and various "non-circumvention" provisions meant to outlaw future weapons that would get around any agreement eventually worked out.

The first movement toward the European view came in September when Secretary of State Alexander M. Haig Jr. told a press conference in West Germany that the United States hadn't ruled out the zero-level option. Then NATO ministers worked this "possibility" into an official alliance communique last month that Defense Secretary Caspar W. Weinberger agreed to, though reportedly reluctantly.

Since then, sources here say the idea has received increasing attention in the administration and at his press conference Tuesday, Reagan spoke of his hope that talks would reduce such weapons "to the lowest point possible."

At the same time, sources say there is little expectation that the Soviets would accept dismantling of much of their SS20 force and thus the negotiations may stretch into a lengthy debate about what, if anything, is workable.

These sources say the missile levels undoubtedly will receive primary attention in initial talks but that the real negotiations will be over what weapons are to be included.

The Soviets, for example, want to include all U.S. aircraft based in Europe capable of reaching the Soviet Union with atomic weapons. The United States does not want to do this and officials say the Americans will claim that Moscow must also include all its aircraft capable of bombing NATO countries in any such accounting.