Fairfax County School Superintendent William J. Burkholder proposed last night increasing the county's education budget by 4.7 percent to $531.2 million, giving all school employes 4 percent raises and funding the region's first high school for science and technology.

Although total spending would increase by $23.8 million, the budget would not require an increase in the county property tax rate because of anticipated revenue increases derived from taxes paid on newly completed commercial and residential development.

The budget Burkholder proposed to the County School Board would raise the starting salary of Fairfax teachers next fall from $17,025 to $18,100. The average teacher in the system would be paid about $29,000.

The Fairfax Education Association, which represents about 6,300 teachers, had voted last November to begin a work-to-the-rule job action next Monday to protest what it said was an inadequate proposed salary increase of 4 percent.

But last night the organization said it had temporarily suspended plans for that action in an effort to get some items added to the budget, chiefly money to fund extending the school year from 180 to 183 days.

Burkholder's budget also calls for $1.1 million for additional buses, supplies, textbooks and instructional staff for the Thomas Jefferson High School for Science and Technology.

The so-called magnet school, to open in the fall, will serve students from Fairfax, Prince William and Loudoun counties as well as the cities of Manassas, Manassas Park and Falls Church. More than 1,300 youths, including 1,088 from Fairfax County, have applied for the 600 openings.

Under Burkholder's proposal, the county's share of the total school costs would increase over last year by $28.3 million (8.8 percent) to $349.5 million -- exactly the margin of growth set by the County Board of Supervisors. School officials and the Board of Supervisors, which ultimately approves the budget, agreed in 1982 to limit the increase in the county's share of school spending to the projected growth in county revenues. The rest of the budget is funded by the state and federal governments.

For the second consecutive year, school officials expect the number of students to increase next year and have included in the fiscal 1986 budget money to hire about 90 new teachers and administrators. Under current projections, the school system will have an additional 2,166 students next year, bringing the total number to 126,206.

The largest single item included in $8 million worth of new programs is $483,485 to hire 20 teachers for Grades 1 through 3 in 19 schools that administrators have identified as having "special needs."

In an interview yesterday, Mary Anne Lecos, assistant superintendent for instructional services, said that allocation is tied to a system-wide effort to improve the performance of minority students. A school study last year showed that black and Hispanic students were consistently falling behind their white and Asian classmates in Fairfax on all indicators of achievement. Last year, the School Board voted to spend $425,000 on projects designed to help alleviate this discrepancy.

Donna Caudill, president of the Fairfax Education Association, said last night her organization would support the superintendent's proposed budget, but only if the School Board and the County Board of Supervisors agree to fund several items Burkholder says he wants but has not requested funds for.

"We still believe that Fairfax County needs to address the issue of equitable salaries for educators," Caudill said. "But our feeling is that the superintendent was making a good faith effort to meet our concerns about salaries. We now await a response from the School Board and the Board of Supervisors."

The items the FEA wants funded are on Burkholder's "wish list" of items, totalling $6.8 million, to be funded if money for them can be found. Chief among them is Burkholder's proposal to extend the school year three days, to 183 from the 180 the state requires.

Caudill said the FEA will resume its "work-to-the-rule plans if the School Board or the Board of Supervisors fails to adopt the organization's list of unfunded proposals made by the superintendent."