The American Civil-Liberties Union said yesterday it plan to file suit to overturn a Washington ban on public parades about Iran and called on the Carter administration to rescind its order singling out Iranian students for possible deportation.

In a statement from New York, Ira Glasser, the ACLU's executive director, said the group will go to court today on behalf of Frank Jackalone, organizer of some American and Iranian students who want to march in support of a peaceful settlement of the dispute in which more than 60 Americans are being held hostage in the U.S. Embassy in Tehran.

"Great care must be taken to avoid making the U.S. Constitution itself a hostage to the events in Iran," Glasser said, adding that the ban violates the First Amendment.

The ACLU also criticized President Carter's order to review the immigration status of all 50,000 Iranian students in this country. Glasser said the order issued Tuesday was "selective enforcement" based solely on nationality, and noted the government had made no claim that the deportation of illegal aliens among Iranians was any higher than among other groups of foreigners. He called the action a "very dangerous precedent" and said a team of lawyers was checking its legality.

Washington Mayor Marion Barry denied a permit for the student group to march from Lafayette Park to the Iranian Embassy, on Massachusetts Avenue.