The United States and the Soviet Union appear to be easing their stands on one of the sharpest disputes between them, the one over the large Soviet radar under construction in Siberia near Krasnoyarsk, according to sources both in and outside the government.

The United States has called the facility a major violation of the 1972 Antiballistic Missile Treaty between the two countries. That pact distinguishes between early-warning radar, which it allows, and radar systems for use in so-called battle management. It allows the Soviets to maintain only one of the latter to direct the ABM system around Moscow.

To keep both sides honest, the treaty requires that early-warning radars be installed at the edge of each country, facing outward, rather than closer to the interior, where battle-management radars would have to be.

The new U.S. position appears to be that, while the Krasnoyarsk radar is in a forbidden part of the country, it is, in fact, for early warning purposes. That makes it still a treaty violation, given its location, but not such a threatening one.

Paul H. Nitze, adviser to President Reagan and Secretary of State George P. Shultz on arms control, said unequivocally at a newspaper editors' meeting here last week that the Krasnoyarsk facility is "an early-warning radar."

The Soviets, meanwhile, appear also to be backing off their original position that the Krasnoyarsk unit's only purpose was to track satellites. During recent private conversations here and in Moscow, some Soviet officials have acknowledged to Americans that the radar may have been built "for military purposes" rather than civilian, as one source put it. The Soviets "know they have a problem" with the treaty, this source said.

The two sides are supposed to discuss Krasnoyarsk at a meeting this week in Geneva of the Standing Consultative Commission set up by the 1972 ABM treaty to settle disagreements over its terms.

The Soviet change in attitude on the issue stems, sources said, from realization that even anti-Reagan arms control experts support the president's contention that the Krasnoyarsk radar is a treaty violation. Bipartisan congressional delegations and even U.S. groups of pro-arms-control lawyers and scientists who have visited Soviet officials in Moscow over the past few months have emphasized the need for Kremlin leaders to do something about the radar.

Meanwhile, according to a Reagan administration official, studies are under way in Washington to find a "palatable" solution short of the only publicly announced one of "tearing it down." Some experts say the Soviets could narrow the radar's angle of coverage, thus limiting the area it scans. The United States took a similar step with two of its new phased-array radars in Georgia and Texas after Soviet complaints several years ago that they violated the treaty.

The Soviets also could make it easy for U.S. electronic spy satellites to "read" the radar pulses when testing of the facility begins in the next year or two. The frequencies of early-warning and battle-management radars are sharply different, according to experts.

These experts discount Soviet Ambassador Anatoliy Dobrynin's remark Friday that American scientists would be invited to examine the installation when it becomes operational. "They would have to be able to examine the computers and the sensors," one expert said, "and the Soviets would never allow knowledgeable government scientists to see such equipment."

State Department spokesman Bernard Kalb said yesterday that Dobrynin's statements were "unclear," but that the United States would study any proposal on the subject.

One U.S. nongovernment expert said yesterday that in one meeting the Soviets were told that if the United States takes "them off the hook" on the Krasnoyarsk violation, Reagan officials will want "a quid pro quo." He said that might include a redefinition of "ABM treaty provisions to permit some 'Star Wars' space defense tests to go beyond the laboratory without complaints."

The ability or inability of the two sides to reach a settlement over the central Siberian facility could be a weathervane on future relations between the new Kremlin leadership under Mikhail Gorbachev and the Reagan administration.

The two giant, cement structures to house the transmitter and receiver of the large, fixed, computer-driven phased-array radar were first identified by U.S. intelligence in 1983. Although still under construction, satellite photographs showed that they were were 400 miles north of the closest Soviet border and faced east-northeast instead of south.

The Soviet claim that Krasnoyarsk is a space-tracking radar is discounted by U.S. analysts, who say it resembles other early-warning facilities and is not located in an area where space-tracking would best be done. The U.S. intelligence "consensus," an official said yesterday, is that the radar was built primarily to spot U.S. submarine-launched missiles coming from the northern Pacific. As such, it fills a gap in early-warning radar coverage provided by existing facilities.

An earlier Soviet early-warning radar at Pechora was criticized by U.S. representatives on the Standing Consultative Commission in 1978 for being 150 miles inland from the northern Soviet border along the Barent Sea. The Soviets said it was placed inland because of "technical and practical considerations," which the Carter administration interpreted as meaning that it was too difficult to maintain such a facility along the frigid seacoast.

One U.S. expert said yesterday that to abide by the ABM treaty and achieve the coverage represented by Krasnoyarsk, the Soviets would have had to build two early-warning radar facilities rather than one.