Fairfax County School Superintendent S. John Davis, described by associates as increasingly frustrated in his Northern Virginia job, resigned today to accept the state's top public school position.

With Gov. John N. Dalton at his side, Davis, who has run the Fairfax system-the largest in Virginia and 12th largest in the county-announced he was accepting a $5,000-a-year pay cut to become state superintendent of public instruction.

Davis has run the Fairfax system for nine years, largely to overwhelming praise from teachers, parents, and students. But this spring he suddenly found himself, along with many Washington area superintendents, the object of protests from teachers over what they said were inadequate salary increases.

The protests coupled with a vote of "no confidence" by the country's largest teacher organization, were said by associates to have hurt Davis deeply. Some said Davis saw himself frustrated by the vote and anxious to move to a new position.

Although the position he will assume Aug. 1 in Richmond, places him at the top of an agency with a $950 million-a-year budget, he will not have the same degree of autonomy his Northern Virginia job afforded him. In the $51,000-a-year state job, he will report to both a cabinet-level secretary of education and to a state board.

The Fairfax County Board of Education met in emergency session last night to accept Davis's resignation and plan to begin a search for a successor in June.

"It's a great loss that Jack Davis is moving to a state position," said John F. Herrity, chairman of the Fairfax County supervisors. "I think he was an excellent and strong administrator and I don't think he'll change his stripes once he's in Richmond."

Herrity said he hoped Davis would "interject some of Northern Virginia's problems" into the debate over school funding.

In Richmond, Virginia Education Association (VEA) president Suzanne Kelly said she too was optimistic Davis would be accessible to the teachers and teacher groups such as hers. "We're hoping for an articulate spokesman (for education)," she said.

Davis is expected by many to be a stronger figure than his predecessor, W.E. Campbell, who retires June 30 after four years as state superintendent. Dalton said he expected Davis would bring "a rare combination of proven administrative ability and an intellectual capacity" to the job.

Davis was a top contender for the state job four years ago, but was reportedly blocked by Gov. Mills E. Godwin, who called Davis "soft" on the issue of allowing teachers collective bargaining rights. Both Godwin and Dalton have announced that they are firmly opposed to granting any form of bargaining to public worker unions.

Fairfax County then was one of 18 Virginia localities with collective bargaining agreement and Davis's role in the agreements made him suspect in Godwin's view, according to news accounts. The Virginia Supreme Court has since ruled such agreements illegal.

Dalton said yesterday he had discussed Davishs views on collective bargaining prior to the appointment and Davis said that he would "support the governor's position."

Davis said yesterday that while he regretted leaving Northern Virginia, where he has lived 30 years, he believed that Fairfax's major school problems are being solved.

"We have some rought water right now, but it's going to calm down," Davis said. "I'm always amazed . . . when we have a period of troubled waters in Fairfax County, it somehow seems to bring people closer together."

"I feel quite strongly that whatever happens at the state level has tremendous impact locally," said Davis. "If I can be a part of making it just a little easier for local jurisdictions . . . then I'll be satisfied."

"We lose a very good superintendent, but we gain by having someone as qualified as Jack at the state level," said Rodney Page, chairman of the Fairfax School Board.

The fairfax Board and Davishs leadership, has been a constant critic of the statehs handing of the minimum competency tests and often complained about lack of direction for special education classes. It has also criticized what it felt was increasingly cumbersome amount of paper work caused by state regulation.

"We and other school districts have chaed a little under regulation," said Page.

Henry W. Tulloch, chairman of the State Board of Education, and chairman of the selection committee that picked Davis from 76 candidates, said that Davis was an attractive candidate because he was not afraid to take strong positions, often even when they were opposed to state policy.

"Davis lost [sometimes], but we admired him for standing up to the board," siad Tulloch.

What drew praise from Tulloch, brought criticism from Fairfax Education Association president Bob Hicks, who said that Davis tended to add programs that lacked proper funding and training. But Hicks predicted Davis would make one of the better superintendents Virginia has had and said Davis would find the state job frustrating.

"Virginia is not noted for outstanding education. (Davis) has good ideas, but with the ultra-conservative state board that exists, it will be hard for him to move," Hicks said.

Both Hicks and some officials in Richmond said that events surrounding the Fairfax teachers' protest may have helped Davis's candidacy for state superintendent.

"Virginia is an anti-labor state, said one official yesterday. It tends to regard the teachers in Fairfax as a bunch of troublemakers," said the official who was close to the selection committee. "I think the protest helped him." CAPTION: Picture, S. John Davis, left, listens as Gov. John Dalton announces his appointment. AP