The Prince George's County Board of Education unanimously approved a major administrative reorganization last night that promotes several blacks to high-level positions. The move follows longstanding criticism that minorities were underrepresented in key jobs in the school system, which is 57 percent black.

The reorganization was the first undertaken by Superintendent John A. Murphy, who has been in office one year. Officials billed it as the introduction of a "corporate style of management" to the area's second largest school system, which has 105,000 students in 175 schools. Officials said the changes are aimed at improving accountability among administrators and ultimately at raising student performance.

The reorganization includes appointment of a deputy superintendent, division of the county into six geographical areas rather than the present two, a reshuffling of officials in five administrative divisions and the promotion of six blacks to key administrative posts.

"It's a move back to decentralizing the system," said Board of Education Chairman Angelo Castelli. "It should give more effective management."

The appointment of black employes to head three of the geographical areas and two of the five administrative divisions follows an agreement between the board and the county NAACP that blacks would be promoted to key positions. That agreement, part of a 13-year-old desegregation suit, was submitted to a federal judge last month.

The reorganization comes in the midst of other sweeping changes in the county system: the introduction this fall of 12 magnet schools designed to improve desegregation and 10 predominantly black "compensatory education" schools, which will receive extra funding because officials say they cannot be desegregated. The plan coincides with new hope among residents that the system can turn around under Murphy, that student performance can improve and that the bitter desegregation dispute may be moving toward resolution.

Murphy, who was reached in Massachusetts where he is vacationing, said, "The thrust will be to hold every school accountable . . . . We feel that's what we need to put us over the top academically."

Reaction to the announcement from the black community was varied.

"It's a matter of musical chairs," said Thomas A. Newman Jr., a member of the NAACP and a plaintiff in the desegregation lawsuit. "The key is going to be what kind of input do they have. We can have blacks all over the place, but if they don't have input into decisions, we're just playing a game."

State Sen. Decatur W. Trotter (D-Prince George's), one of several black legislators who has been outspoken on the issue, said he was encouraged but also wanted to withhold judgment. "Because you move one black person does not necessarily resolve the issue. It depends on who that person is and their own sensitivity."

The reorganization includes no appointments from the outside and carries no additional cost, according to school spokesman Brian J. Porter.

"You could call this the beginning of Dr. Murphy's long-range effort to move the school system forward," Porter said. He called it "micro-management" that distributes the responsibilities previously held by a few top administrators to 11 assistant and associate superintendents and a deputy superintendent.

The deputy's position, which has been vacant for the last two years, will be filled by Edward M. Felegy, who previously was assistant superintendent for administration and personnel.

Appointed to head the six areas, which were drawn from north to south in rough slices across the county, were: John Whittington, a coordinating supervisor of instruction; Conrad Koch, an assistant superintendent; Monica Uhlhorn, coordinating director of instruction; Gloria Bolds, principal of Walker Mill Middle School; Jesse Freeman, principal of Francis Scott Key Middle School; Ronald Mortimer, acting assistant superintendent for the Southern Area. Each area includes between 25 and 30 schools.

Appointed to head five administrative divisions were: Louise F. Waynant, from assistant superintendent for instruction and pupil services to associate superintendent for instruction; Anne Prince, from administrative assistant in the Southern Area to associate superintendent for pupil services; Jerome Clark, from administrative assistant in the Northern Area to associate superintendent for personnel; George Ridler, from budget director to associate superintendent for adminstration; Patricia Palmer, from assistant superintendent for supporting services to associate superintendent for supporting services.

Clark, Prince, Bolds, Freeman and Whittington are black. A sixth black employe, Nancy Bishop, was promoted from supervisor for mathematics to director of staff development.

Daniel Saltrick, formerly administrative assistant for instruction and pupil services, was appointed as director of instruction and curriculum.