Under unusually heavy police escort, about 70 anti-shah Iranian students marched peacefully on the Iranian Embassy yesterday - in sharp contrast to violent Iranian demonstrations at the White House Nov. 15.

The students, many wearing masks and shouting "Death to the shah" in their native Persian, marched under cold bright skies through downtown Washington and out massachusetts Avenue NW where police, by prior stopped them near the embassy at 3005 Massachusetts Ave.

The police show of force, which itself swelled to more than 70 uniformed officers and assorted plainclothes agents at one point, was a clear reactioni to the Nov. 15 clash and the students' newly acquired reputation for violence.

But yesterday's march went off smoothly and without incident. With D.C. polic escootermen shepherding them along, the marchers kept on the sidewalks and maintained a close discipline. They had even removed the wooden stick had even removed the wooden sticks from their placards - often used as clubs in past violence - and carried the placards on strings around their necks.

On the way to the embasst, as they passed by Lafayette Park - from which they were barred by the National Park Service because of the Nov. 15 violence - police massed in heavy numbers.

Two U.S. Park Police camera crews shot film of the marchers. An array of civilian-dress officials including Secret Service agents and observers from the D.C. police and Interior Department legal offices, the mayor's command center and the Justice Department's community relations service, also watched as the student shouted, "Carter's human rights means fascism in Iran" and "The shah kills the people, the people take up arms."

Massoud Amini, one of the protest organizers, shouted over a loud-speaker that "hundreds have been killed and arrested in Iran" during a recent crackdown on policitcal dissidents by Shah Nohammad Reza Pahlvai.

He said President Carter's scheduled visit to Iran late this month should be canceled and AMerican military aid withdrawn.

Amini, who said he is a student at George Mason University, told The Washington Post the Iranians plan a court challenge of the refusal earlier this week by the National Park Service to let them rally in Lafayette Park yesterday.

The park service, citing a "clear and present danger to public safety" because of the Nov. 15 violence on the Ellipse in which more than 100 persons were injured, denied the Iranians' request for a demonstration permit. Park officials said it was the first time in their memory that such a request has been denied on the "clear and present danger" principle.

James R. Klimaski, an attorney representing the Iranian Students Association in the U.S. has already asked the park service for all official documents in connectiion with the decision to deny the permit. He said the documents may help form the basis for a constitutioal challenge of the denial.

Rep. Don Edwards (D-Calif.) also wrote to Interior Secretary Cecil D. Andrus, who has authority over the park service, and questionaed the constitutionality of the permit denial.

Edwards asked Andrus to reverse the park service action. An Interior Department spokesman said yesterday Andrus turned Edwards' letter over to departmental lawayers for consideration but said Andrus "did not see any compelling reason" to reverse the park service in the Iranians' case.

Several hundred stick-swinging antishah students attacked pro-shah demonstrators on the Ellipse on Nov. 15 during the shah's ceremonial arrival at the White House. Scores of persons were injured before Park police routed the students with tear gas. Demonstration organizers denied initiationg the violence, blaming provocateurs for SAVAK, the Iranian secret police.