About 75 Polish-Americans and their supporters picketed near the Polish Embassy in Northwest Washington yesterday, burning two Soviet flags and singing the Polish national anthem in protest over the imposition of martial law in Poland.

Yesterday's demonstration was part of what has become an almost daily series of protests by the area's small but vocal Polish-American community, which has staged several events near the embassy. Several demonstrators said their spirits were buoyed by the announcement yesterday that Polish Ambassador Romuald Spasowski has asked for political asylum here, but added that they felt it would have little long-range impact.

"I love him for today for what he did," said Jurek Samotyj, 32, a McLean building contractor who was one of the organizers of yesterday's demonstration, "But what difference will this make with the Russians? Not much, I think."

Samotyj and others said they believe that only prolonged and worldwide public pressure will prevent further bloodshed and repression of the Solidarity union movement.

Carrying red and white Polish flags and banners calling for a free Poland, demonstrators watched as Samotyj set fire to two kerosene-soaked Soviet flags. The flags were held by Kris Ludwiniak, a former state prosecutor from Warsaw, who said he fled Poland in 1973 in protest over "many injustices" he saw as a prosecutor.

As the flags burned, demonstrators shouted "Down with Russia." Once the flames burned out, they doffed their hats in the frigid wind and sang the Polish national anthem as they stood clustered on a traffic island at 16th Street and Columbia Road NW. City law bars demonstrations within 500 feet of an embassy.

"All my family is still in Poland. All my friends. My parents, my sisters, my cousins," said Elisabetha Chlopecka, 29, an attorney and translator who came here last January on what she thought would be a six-month visit. She now is unsure when, if at all, she will return to her home in Bydgoszcz.

"I am busy now trying to help organize this demonstration because I am trying not to think about my family," Chlopecka said, "I am trying to show my people that I am with them, even if I can't be with them."

Meanwhile, 4,000 people jammed into St. Patrick's Cathedral in New York yesterday for a special mass for Poland, at which Cardinal Terence Cooke decried the bloodshed and called on all freedom-loving people to express solidarity with the Poles.

"Today we pray that the way of peace and justice might be prepared for the people of Poland," he said.