A Fairfax County judge yesterday upheld a Virginia athletic league's sanctions against the Mount Vernon High School basketball team, a decision that will keep the Majors from participating in next week's postseason playoffs.

The members of the basketball team had asked the courts to lift temporarily the restrictions imposed against the school last year for alleged basketball recruiting violations.

Attorneys for team members argued the Virginia High School League overstepped its authority when it levied the sanctions. The VHSL contended that it was acting within its authority.

Circuit Court Judge Lewis H. Griffith ruled the league was justified in administering the punishment, but admonished local school officials for taking the controversy to state authorities.

"The student suffers the brunt of this punishment," said Griffith. "But it all could have been avoided if it had been handled at the local level at the inception of the problem."

Many of the parents and coaches of Mount Vernon basketball players who had observed the two-day hearing left the courtroom in tears early last night after the decision.

"We could go on to the Supreme Court," said a dejected Gerald A. Fill, Mount Vernon district representative on the county school board. "But it's too late."

The team members asked for the temporary injunction so the Majors could play in the Gunston District playoffs, which begin Monday.

Yesterday's hearing was part of the continuing and sometimes heated confrontation between county and state officials that began almost 1 1/2 years ago when officials at Alexandria's T. C. Williams High School accused Mount Vernon officials of attempting to recruit out-of-district students for its basketball team. Recruiting students across district lines is against the rules of the VHSL, the state association of high school athletic teams.

A VHSL committee last May found Mount Vernon violated the rules by attempting to recruit seven players from outside its district. It placed the school on a one-year probation, barring it from district and postseason championship games.

When Fairfax County officials asked the association to reconsider its decision, the VHSL came back with even tougher sanctions, extending the probation to the 1983-84 playing season.

Members of this year's basketball team went to court in an effort to convince the judge that they were being treated unfairly for the alleged violations of previous years.

Mount Vernon officials have steadfastly denied they attempted to recruit basketball players. They contend out-of-district students playing on the team are attending the school because of special education and other academic programs, rather than because of athletics.

The controversy last year pitted county school board members against its own hired administrators, who requested the VHSL investigation without consulting the school board. When board members asked for tapes of the committee's investigative hearings, Linton Deck, who was then superintendent, said the tapes had been destroyed.