The United States will "study" new arms control proposals made last week by Soviet President Yuri V. Andropov and "will address them" at talks under way in Geneva on limiting medium-range missiles, President Reagan said yesterday in his weekly radio address to the nation.

Reagan's response to the Soviet proposals seemed slightly more positive than the first reaction last Thursday by the State Department, which was that Andropov appeared to be offering "little new" while still insisting on "unacceptable conditions for any agreement."

Reagan in his speech also called attention to the NATO decision, announced Thursday in Canada, to withdraw unilaterally an additional 1,400 U.S. atomic weapons over the next five or six years from a stockpile in western Europe unofficially estimated at 6,000 weapons.

The United States withdrew 1,000 such weapons in 1980. The president indicated in his speech that he hopes this further withdrawal will be welcomed as good news by Europeans concerned over the deployment, scheduled to begin in December, of the first of 572 new U.S. Pershing II and cruise missiles on European soil.

Reagan's mention of the long-planned NATO withdrawal also may have been intended to help offset unease in Europe over the surprise U.S. invasion of Grenada last Tuesday.

It also was learned yesterday that the administration probably will decide this week whether to lift some sanctions against Poland that were imposed after the 1981 martial law crackdown in that country. Sources said the administration was considering lifting restrictions on Polish fishing in American waters and rescheduling part of the huge Polish debt to the West. A U.S. decision to lift some sanctions would be welcomed in Europe.

Commenting on Andropov's latest offer at the talks, which are meant to find a way to limit the U.S. deployment and about 600 Soviet missiles already fielded, Reagan said that, "unfortunately," the Soviet proposal would continue a Soviet missile monopoly in Europe while not allowing any U.S. missiles to balance the Soviet force.

The president also criticized the Soviet leader for coupling his proposal "with an explicit threat to break off" the Geneva negotiations if the United States begins its deployment as planned.

Nevertheless, senior officials briefing reporters on the Reagan speech said the administration was "prepared to negotiate on the Soviet proposals, has not rejected them out of hand and wants to stay at Geneva" and keep the arms talks going.

Asked what was responsible for the apparent shift in tone from the State Department reaction Thursday, one official said he thought the administration had not decided how to respond to the Andropov proposal and therefore did not want to reject it out of hand.

Both superpowers are heading for a showdown as the December deployment nears for the new U.S. weapons. Moscow is making its proposals in public, seeking to turn European opinion against allowing the deployment. The Reagan administration is emphasizing its commitment to negotiations and U.S. concessions at the talks to maintain credibility among citizens of West Germany, Italy and Britain, where the missiles are to be installed.

The latest Andropov proposal would drop the number of Soviet triple-warhead SS20 missiles allowed in Europe to 140, the lowest number yet proposed by the Soviets, but it still would preclude deployment of any U.S. missiles in Europe to balance the Soviets'. It also would freeze Soviet missile deployments in Asia at the current level of 108 and suggests some as yet undefined willingness to compromise on aircraft in Europe.

American specialists say that the Soviets appear to be moving toward reductions in numbers of missiles and to recognize American concerns about Soviet missiles in Asia as well as Europe. Nevertheless, the two sides are far apart. The administration has said it wants to keep negotiating and would withdraw missiles that were installed if an agreement can be reached at any time.

The president pointed out that since NATO decided in 1979 to begin deploying missiles in 1983 if no arms accord is reached, the Soviets have added 200 SS20 missiles and 600 atomic warheads to their arsenal. The White House says Moscow has no grounds to quit the talks if the U.S. deployment now begins.

On the withdrawal of older atomic weapons, Reagan said the idea is to keep in Europe only as many as are necessary to maintain deterrence of a Soviet attack.

Administration officials said that the United States, after this withdrawal, will have fewer atomic weapons in Europe than at any time in the last 20 years and that the Soviets already have a 3-to-1 advantage in the number of such weapons in eastern Europe and the western Soviet Union.