A U.S. District judge ruled here yesterday that a former Justice Department employe was illegally fired from her job in the department's community relations service because she refused to submit to sexual advances of her supervisor.

The decision of Judge Charles R. Richey was in the case of Diane R. Williams, 32, now a law student. She first charged eight years ago that she lost her job because she spurned her boss.

Richey found that it was "more likely that not" that Williams' refusal to submit to "social) and sexual" advances from her superior substantially affected the way she was treated on the job.

Williams was fired in September 1972 from the Justice Department, where she had worked as a public information specialist.

Richey noted in his opinion that it was only after Williams rejected the sexual advances that "criticism of her work" began. Richey found that evidence in the case showed that "her rejections of the advances spawned the criticism of her work and eventually led to her dismissal."

The supervisor, Harvey Brinson, now a GS-15 public affairs officer at Justice, denied making any advances toward Williams. In the opinion, however, Richey wrote that he found that particular testimony "notably incredible," considering Brinson's testimony that he had sent Williams a "suggestive" greeting card and had a sexual affair with her which Williams vigorously denied.

During a four-day trial, Brinson contended that Williams had initiated their alleged sexual relationship and that she had retaliated against him when he broke off the affair "by refusing to do her job and getting herself fired," Richey wrote.

The judge, recalling that Brinson had denied the existence of any affair in pretrial proceedings, said the court had to reject Brinson's "12th hour revision of the events."

Moreover, Richey said, the atmosphere in the community relations office at the Justice Department was such that an employe such as Williams "would realize that sexual submissiveness would be rewarded (in that office) by Mr. Brinson."

Richey said in his opinion that Brinson admitted he had an affair with another female subordinate in that office and that "knowledge of this affair traveled throughout the agency."

"in such circumstances, it would be natural for an assumption to develop in the minds of women such as [Williams] that submission to the advances of Mr. Brinson would smooth the path to promotion," Richey wrote.

In 1976, Richey made a similar ruling in the Williams case, but the case was returned to him by the U.S. Court of Appeals for a full trial on the facts. At the time, Richey had awarded Williams $19,147 in lost pay. The question of damages will now be reviewed a second time.

In his original decision, Richey ruled -- in the first case of its kind -- that employes could sue their bosses for sex discrimination if submission to sexual advances was a condition for employment.