The D.C. Council, despite strong objections from trustees of the University of the District of Columbia, ordered the school last night to vacate its main School of Education building by mid-August and turn it over to a new city-run law school.

The council voted last year to establish the law school to rescue the Antioch School of Law, which is scheduled to close. But because of continued opposition from Mayor Marion Barry, a classroom facility for the new venture had not been found.

Council member Hilda H.M. Mason (Statehood-At Large) offered the takeover measure as emergency legislation, saying the move was necessary to gain approval from the American Bar Association for the law school to begin recruiting a new class.

In an unusual sequence, the measure fell one vote short of the nine votes required to declare an emergency.

But council member Betty Ann Kane (D-At Large), an opponent of rescuing Antioch Law, then asked for the matter to be reconsidered, and, on the subsequent voice vote, allowed the emergency to be declared.

The bill then passed 8 to 4, one vote more than the number needed for this step, with Kane voting against it.

Kane said she took the unusual steps because she hoped that members of the council majority who expressed reservations about the law school, but voted for it anyway, "would stop playing games." She urged Barry to veto the bill.

Last night, Dwight S. Cropp, the mayor's director of intergovernmental relations, said he was uncertain what action Barry would take on the bill.

The building that would be transferred is a 74-year-old structure at 11th and Harvard streets NW, which for many years housed the old Wilson Teachers College. It then became part of D.C. Teachers College, one of the three institutions that merged to form UDC 10 years ago.

It now holds classes for about 2,200 students and offices for 55 faculty members.

Several hours before the council vote, the UDC board unanimously passed a resolution denouncing the "confiscation" of the building, which is owned by the District government.

After the vote, N. Joyce Payne, chairman of the UDC trustees, called the action an "unconscionable tactic" that would "guarantee space for a law school that has absolutely no assurance of accreditation by displacing 2,200 students from their classes."

In other business last night, the council approved a new benefits plan for District employes hired after Oct. 1 that would gradually wean workers from the Civil Service Retirement System and the Federal Employees Retirement System.

Although the Metropolitan Washington Council of the AFL-CIO dropped its objections to the measure after testifying against it during public hearings, the American Federation of Government Employees maintained last night that the council was "patently irresponsible" and was reducing retirement benefits for D.C. employes.

The plan would cost the District significantly less than the federal government's benefits program.