Washington — In what amounts to mostly symbolic gestures, the Reagan administration has decided to lift some of its economic sanctions against the Soviet Union and Poland.
The decision, announced this week, to end a ban on Soviet fishing in American waters was made in part to send a signal to the Soviets that the administration wants to improve US-Soviet relations.
A separate decision to lift a ban against Polish airline flights to this country, expected to be made public next week, comes in response to Poland's recently announced amnesty for political prisoners.
The administration is also expected to restore government-funded scientific exchanges with Poland, officials say.
In the view of some administration officials, the move to lift the fishing ban against the Soviet Union apparently could be of some political benefit to President Reagan in an election year. It comes at a time when the Democrats are accusing the President of failing to negotiate effectively and improve relations with the Soviets.
A State Department spokesman indicated the lifting of the fishing prohibition had a dual purpose. He said the move would provide greater employment opportunities and other benefits to American fishermen. But he also said it was consistent with President Reagan's ''policy of promoting a constructive dialogue with the Soviet Union and facilitating nonstrategic trade exchanges.''
According to the State Department, Soviet fishermen would be allowed to catch 50,000 metric tons of fish off Alaska and the West Coast of the United States. The Soviets would be expected to buy an equal amount of fish from American fishermen, in addition to fish purchased through joint fishing ventures that are already in place.
The fishing embargo was imposed by President Carter in early 1980 shortly after the Soviets invaded Afghanistan. Before the invasion, a fisheries agreement allowed Soviet fishermen to take 400,000 tons of fish from American waters.
The sanctions that followed the invasion also included restrictions on the export of American oil and gas equipment to the Soviets and an embargo on grain sales. Arguing that the grain embargo did more damage to American farmers than it did to the Soviets, President Reagan in 1981 lifted the sanction against grain sales.
In the case of Poland, the administration has cautiously welcomed the Polish authorities' recent decision to grant amnesty to political prisoners. An administration official said a decision had been made to lift the US ban against Polish airline flights and to restore scientific exchanges.
Polish government officials have expressed disappointment that this may be the extent of American response to the amnesty. But the American official said the Reagan administration is also considering the possibility of restoring Poland's most-favored-nation trading status. President Reagan had suspended the Eastern European country's trade standing in 1982 in retaliation for Poland's abolition of the independent Solidarity trade union movement.
Before most-favored-nation status could be restored, however, there would have to be careful consultation with the US Congress, a State Department official said.
One reason for the administration's caution is that the Polish amnesty is reversible. Richard Davies, a former US ambassador to Poland, points out that the political prisoners, in effect, are being released on parole. Some of them could easily be arrested again.
''We want to see who is released, under what conditions, if there are any new arrests, and what this means to the human rights situation in general,'' says a State Department official. The US, he adds, will be watching any Polish moves toward economic reforms as much as anything else.
Edward J. Derwinski, the counselor of the State Department, says the American reaction could not consist of any ''grand, sweeping package,'' but must be ''a step-by-step process'' based on a determination that a real liberalization was occurring.
Mr. Derwinski is a former Republican congressman who closely follows developments in Polish-American relations.