The Soviets are airing their views about future relations with the Reagan administration in which they combine the hope for a new strategic understanding with the determination to maintain military parity at any cost.

Prior to the first high-level contact with the new administration, however, they are making no secret of their feeling that their hope of this past winter that the Reagan administration would mute its hostility once in office has been disappointed and that the American desire for a stable East-West relationship no longer can be taken for granted.

Thus the meetings Wednesday and next Monday between Foreign Minister Andrei Gromyko and Secretary of State Alexander M. Haig Jr. are regarded here as among the most important encounters between the two superpowers in quite a while.

What Gromyko and Haig tell each other in New York will affect the climate of U.S.-Soviet relations in crucial ways. At stake are not only their private assessments of each other's interests and presumed ambitions, but also the chances of containing the arms race.

The public record of an assertive Reagan foreign policy and the sharp increase in U.S. defense spending can explain the alarm in the Kremlin, but there seem to be even more distressing policy concerns that are discussed only privately here.

The Americans are seen as moving aggressively toward military superiority. Much has been made of Reagan's decision to produce and stockpile the neutron warhead, since the nature of the device -- it kills by enhanced radiation while doing relatively little damage to structures -- lends itself to antinuclear propaganda drives.

Kremlin leaders, however, are privately far more concerned about other new weapons systems. They worry, for example, about the space shuttle and its possible military uses. Should the United States turn the shuttle into an outer space weapons system, the Soviets would have to commit vast resources to match it.

So far, there has been only one public suggestion that Moscow has started its own new strategic programs. All authoritative pronouncements here have coupled calls for new arms control talks with the professed intentions to match American weapons development if necessary.

This policy indicates that for the time being the Kremlin intends to rely on political and propaganda means to erode support in Western Europe for Reagan's policies. From Moscow's point of view, the most pressing goal is to block the planned deployment of new U.S. medium-range nuclear missiles in Western Europe. If deployed, these weapons would change the strategic balance immediately, according to Soviet analysts.

Moscow's long-term attitudes are less clear. But the Soviets still hope that economic considerations and antiwar sentiment in the United States may limit the American rearmament program and that the administration eventually would have to reach some form of strategic understanding with Moscow.

From Moscow's point of view, this is all taking place in the absence of dialogue between the two superpowers. Although there has been correspondence between the two governments, it is evident that the Soviets are unhappy with the substance of American communications and that they have come to believe that Reagan's public pronouncements may reflect accurately the intentions of his administration.

While they first thought Reagan's initial rhetoric would be adjusted to world realities, Soviet analysts now believe that the Americans are serious about gaining strategic superiority over the Soviet Union and that they intend to use future arms-control talks as another tool for containing Soviet power. So far, American arms-control proposals are viewed here as public relations gimmicks to mollify public opinion in the West while gaining time needed to initiate programs aimed at strategic superiority.

The Reagan challenge comes at a time of economic and political crisis within the Soviet orbit. The internal strains were revealed first in Poland, because of Polish history and circumstances. But other Soviet allies face similar economic problems and even Moscow has had to import huge amounts of grain after the third bad harvest in a row.

With the increase of its military power in the 1970s, the Kremlin also has extended its sphere of influence. But that means that new clients such as Afghanistan, Laos and Cambodia have joined Vietnam, Cuba, Mongolia and Eastern Europe to claim Soviet resources, arms and other assistance.

Poland, in particular, is a grave political challenge. To crush the Polish rebellion would only exacerbate Moscow's problems because it would destroy carefully cultivated political and economic ties with Western Europe, and ensure not only the NATO deployment of new U.S. missiles but also a new round in the arms race.

The suspicion here is that the United States might really want an arms race. Or, to put it differently, some here believe the Reagan administration thinks that the Soviet drive to reach the status of a global power will overload its economic and political base.

Gromyko's task in New York is to provide the answer to these questions.

One thing that comes through with ringing clarity at every level here is that the Soviet Union will not permit the United States to change the current military balance and that Moscow is prepared to pay any price to make sure that does not happen.

Soviet officials and commentators maintain publicly and privately that it would be a serious delusion to believe that the Americans can force the Soviets to take a second place again.

By virtue of its size and resources, the Soviet Union is one of the richest countries in the world. Its government is so centralized that it can mobilize its resources quickly and focus them in any desired direction. Its people are still believed capable of enduring sacrifices most Americans would not tolerate.

As the latest issue of Novoe Vremya (New Times) put it, "The powerful scientific technical potential resting on sufficient natural resources allows the Soviet Union to respond to any challenge."

In part, of course, this is brave talk. But the Soviets have taken some practical steps. These include precautionary food rationing and sharp increases in the prices of consumer goods (including the doubling of the domestic retail price of gasoline to $2.20 per gallon). These steps seem designed to tighten political and economic discipline and prepare the people for possible future privations.

Behind Moscow's unyielding position on the strategic balance, senior Western diplomats say, are two main objectives of Soviet policy.

One is to involve the Reagan administration in the arms control process by starting talks on limiting medium-range nuclear weapons in Europe. Once the talks get under way, according to this thinking, the Soviets expect that it will be far more difficult for the United States to start deployment of its new cruise and Pershing II missiles.

But the basic and long-term assessment to be made by Gromyko in his talks with Haig is whether there are real chances for a modest agreement to limit the pace of the development of central strategic weapons systems.

The Soviets are no longer in the mood to explain away extremely disturbing evidence of hostile U.S. intentions. The Kremlin is believed to be under pressure from its military to get on with new weapons programs.