Chief Judge Harold H. Greene of the D.C. Superior Court lifted yesterday his order barring demolition of the historic Dunbar High School building, thereby appearing to remove the last obstacle to tearing down the structure.

The city wants to demolish the 61-year-old school on 1st Street between N and O Streets NW and use the site to build a stadium for the new Dunbar, which opened April 12 one block away.

Alumni of the famous school, whose list of graduates reads like a black "Who's Who," went to court in an attempt to preserve the building. They emphasized its historic and symbolic significance.

In issuing arr order April 1 preventing demolition of the dark red brick structure, with its crenellated towers and stone detailing, Judge Greene cited a regulation of the city's building code.

Under the code, Greene said, the city is required to make a good faith effect to hear and consider views of civic groups, public agencies and interested citizens on possible alternatives to demolition.

In addition, Greene said that the city previously failed to engage in "meaningful negotiations."

In lifting the ban on demolition Greene said yesterday that "meaning negotiations" as required by the building code have been held.

He said three public negotiating sessions were held at which city officials "genuinely heard, condidered and ultimately rejected alternatives to demolition."

Asserting that the court's role is only to ensure compliance with regulations and other safeguards, he said the decision on razing the school is for the executive branch, not the judiciary.

Demolition had been planned for April 1, and it could not be immediately determined last night if a new date has yet been set.

In addition, there was no immediate word on whether the Dunbar Alumni-Association comtemplates further efforts to preserve the building, which has been placed on the Inventory of Historic Sites.

Dunbar is the city's oldest black secondary school and was particularly prominent in the era of segregated education when it achieved a nationwide reputation for academic excellence.

"To us, tearing down Dunbar High School is like somebody trying to tear down the Washington Monument or the Capitol; it might be hyperbole, but that's how we feel," Dr. Henry S. Robinson, a Dunbar graduate who was then a City Council member, told the Council during a 1974 debate on the issue.

In a newspaper interview, Dunbar principal Phyllis R. Beckwith said that while she understood the graduates' concern, "I have to . . . deal with the needs of my students. The fact is we have no atheltic field and no adequate gymnasium . . ."

She addded: "My concern is that these black students in this area get 100 per cent of what they deserve."