The director of the federally financed National School Safety Center caused friction among his staff, but did not mismanage the facility and completed most of the program objectives, congressional investigators concluded yesterday.

The General Accounting Office report said staff upheavals at the center based in Sacramento, Calif., stemmed from Director George Nicholson's "combative style" and disagreements over the center's program.

Nicholson was the unsuccessful Republican candidate for California attorney general in 1982.

The GAO report was issued after a two-month investigation and interviews with 19 persons, including the president of Pepperdine University, which administers the center. "We found no basis to question the center's furniture purchases, use of consultants, and use of its facilities to conduct a Pepperdine masters degree program, all of which former staff members have alleged to have been improper," the GAO said.

The center's purpose is to restore school safety and discipline through a comprehensive national program of training, technical assistance and coordination for school officials and others.

The center was established with a $3.8 million noncompetitive grant by the Justice Department's Office of Juvenile Justice and Delinquency Prevention.

The report concluded that the center finished 75 percent of its programs scheduled for completion in its first grant year as well as 96 percent of the tasks that had no specific deadlines.

The probe was ordered after center employes complained of staff upheavals, paralysis in programs and improper expenditures. Since the center opened June 1, 1984, two-thirds of the 30 staff members have either been fired or quit.