A Virginia legislative committee, after a 2 1/2-hour closed meeting, voted unanimously today to support the reappointment of a district court judge who had been accused of public and private misconduct while off the bench.

"I'm happy," was the only comment of Judge David G. Simpson. The action by the House Courts of Justice Committee is a major step toward another six-year term for Simpson as General District Court judge for Winchester and Frederick County. Simpson still must be approved by the corresponding Senate committee.

Del. Clinton Miller (R-Shenandoah) said there was "never an allegation that he didn't, while on the bench, perform well."

Miller added that the evidence "did not fully support the bulk of the allegations."

Kenneth Y. Stiles, chairman of the Frederick County Board of Supervisors, was a leader of the movement to oust Simpson.

In December, Stiles and D. Mitchell Basker, a former magistrate fired by Simpson, urged both the House and Senate courts committees not to reappoint Simpson, whose term expires July 1.

This week, Basker wrote to the two committees asking that Simpson be required to answer, under oath, allegations of misconduct.

In his letter, Basker said two female lawyers were so "intimidated" by Simpson's "alleged tirade of drunken, vulgar, crude, vile and sexually demeaning language" at a bar association picnic that they will "never again attend organized bar functions."

Neither woman could be reached for comment today.

Basker also contended that at a wine and cheese party at the home of a physician, Simpson "was observed to be drunk on the floor, imitating a dog, making animal noises" and making obscene gestures and remarks.

Simpson refused to comment publicly today on those and other allegations.

Del. Alson H. Smith Jr. (D-Frederick), the delegate from Simpson's district, said he will renominate Simpson at a meeting of the House Democratic Caucus, which Smith heads.

Judicial candidates are nominated by the Democratic and Republican caucuses in the two houses and "elected" by the full membership of the General Assembly.

Miller said that after its last meeting on the nomination, the committee "indicated reservations" on Simpson's reappointment. Today, Miller said, "a lot of allegations that had been presented were rebutted" by Simpson. "Even those opposed to him agreed that, basically, as far as being a judge, there was no complaint."

Miller, a lawyer, said he has practiced before Simpson and "never had a problem."

Among 16 persons appearing in support of Simpson today were Thomas W. Dickinson, president of the Winchester-Frederick County Bar Association, who said the members voted unanimously in support of Simpson in December; Charles Anderson, deputy sheriff representing the Winchester chapter of the Fraternal Order of Police, the clerks of two local courts and several lawyers.

Simpson's supporters were permitted to stay during the testimony, but Del. C. Hardaway Marks (D-Hopewell), the committee chairman, ordered a reporter to leave.

Simpson, 51, was named a part-time judge in 1972, and elected to his first six-year, full-time term in 1980.