There has been a distinct change of tone in Soviet assessments of the Reagan administration, as Moscow has come to believe that the United States is trying to use the Polish crisis "to change the map of Europe," according to well-informed Soviet officials.

If so, these officials say, the Americans are playing with fire that could produce an explosive situation in East-West relations.

Kremlin leaders are described as being "indignant" over what they see as "hypocritical" U.S. efforts to destabilize the European balance of power brought about by "the results of World War II," the officials said.

The term "results of World War II" is political shorthand here for the wartime division of Europe. It is equivalent to the term "Yalta" used in the West for agreements reached by Soviet leader Joseph Stalin, U.S. president Franklin D. Roosevelt and British prime minister Winston Churchill on the postwar borders of Europe.

"It seems to us that the goal of the Reagan administration is to destroy us," one official said. "If that is so, we are ready to face it; we are ready for confrontation."

As seen from here, there are two aspects of U.S. intentions that have emerged in the past four weeks that are particularly galling to Moscow.

One is that Reagan appears intent on pursuing a political and propaganda struggle to prevent a speedy consolidation of authority of the pro-Soviet forces in Poland. This is seen as an attempt to reverse "the results of World War II" in an area conceded to Moscow and with the most vital security implications for it.

The second is to use the Polish crisis to pressure reluctant West Europeans into creating an "anti-Soviet front" in the West. The fact that NATO countries rallied behind Reagan with a denunciation of Polish repression in itself is not seen as having an immediate impact. The allies did not follow Reagan's lead in adopting economic sanctions. But the Brussels decision is seen here as a potentially dangerous framework for future U.S. pressure.

In contrast to the 1970s, when the Americans were interested in European "stability," sources here say, Reagan's policy toward Poland since the military crackdown has ushered in what one source called "dangerous adventurism when anything can be expected from the United States, including a nuclear war."

To a greater degree than four weeks ago, when the change of accent began to be heard following the American reaction to the declaration of martial law in Poland, Soviet officials now say that whatever amount of good will was left toward the Reagan administration is being "destroyed."

While it had held a dim view of Reagan's intentions in view of his military buildup, Moscow now professes to see "very dangerous and bellicose plans" by Washington aimed at changing "the European security base."

"They simply don't care about our security interests but only their own," an official said. "It is a dangerous illusion to believe that the United States is strong enough for that."

The Kremlin appears to fear that continued propaganda and political warfare over Poland may damage chances for the "normalization of the situation" there. This in turn may have an effect on the rest of Eastern Europe and on the internal situation in the Soviet Union as well.

This is a highly delicate matter because Moscow's security policy has been based on the Yalta treaty that eventually led to Soviet domination over Eastern Europe.

At Yalta in 1945, the three wartime leaders agreed that free elections should be held in Poland and that the provisional Polish government should be broadened to include democratic elements. But neither occurred and a Communist government took control.

In October 1944 Churchill and Stalin had informally agreed on how much influence East and West should have in the rest of Eastern Europe.

By the 50s the Soviet Union had full control over Eastern Europe. During the Cold War period, the United States tried, at least rhetorically, to "roll back" that Soviet influence.

Then followed the period of detente culminating in the 1975 Helsinki accords that formally recognized European post-war borders.

"The general feeling here is that they the Reagan administration have decided to have a confrontation with us," one Soviet official said. "They had expected that the Polish Army would collapse and they wanted to see a Soviet intervention because that would make things easier for them."

Another official suggested that Reagan had "inherited the weaknesses of the previous administration and wants to change that. But this cannot be done in one year with the use of rhetoric.

"So we are back to rollback policy, but this is now very much more dangerous than in the '50s."

Publicly, however, the Soviets are more circumspect, since they still expect that Western Europe ultimately will not follow Reagan. The policy of selective detente seeking to divide Europeans from the United States requires sober calculations and cautious shifts.

There was an almost aggrieved tone in the Soviet government response to the Brussels decision. It blamed the Americans for engineering it for their "excessive political ambitions" and called it "an outrage upon the most sacred norms of relations between states and upon international law."

Private comments indicate that, as one official put it, Soviet-U.S. relations have entered "a black period."

In part, such comments may be designed for propaganda purposes. Seasoned diplomats here say that the Soviets still are prepared to talk to Reagan, indeed that they are quite eager to establish a dialogue.

At the same time there are pressures for military decisions here in view of what is seen as erratic and unpredictable U.S. policy.