The General Services Administration will begin negotiations with Fairfax County next week over a 107-acre tract of surplus federal property along U.S. Rte. 1 that once was considered as a Virginia prison site.

Fairfax County Executive J. Hamilton Lambert asked the GSA in February how much it would cost to buy the land, once part of Fort Belvoir, and if there was a possibility of a no-cost transfer. The county would like to use the land for a park.

In a letter GSA regional officials in Atlanta drafted this week, the agency will tell Fairfax that the Reagan administration's policy is to sell, rather than give away, unneeded federal property. The agency will give the county a confidential estimate of the site's worth.

John L. McBride, Fairfax's director of property management, said the county has "no funding for it right now. When we get the price, we will have to decide if we want it still." McBride said several county supervisors had expressed concern about losing the chance to purchase the open land in a section of the county that "needs more park land."

"We just don't want to miss the opportunity and end up with commercial development," he said.

After the Army gave the former training facility to GSA for disposal in 1979, it was highly sought after. The State Department said it wanted it for an antiterrorist training facility, but eventually withdrew the proposal. Virginia Gov. Charles S. Robb eyed it as a site for a new state prison but quickly scuttled the proposal after a public outcry.

Lambert said he wanted a GSA appraisal that takes into account the county's comprehensive plan and the nearby Pohick Church Historic District Zoning, which make it "prudent that the appraised value of the subject parcel should reflect a park use."

James Buckley, GSA's deputy assistant commissioner for real property, said that the appraisal would be based on residental use.

"We cannot discuss the appraisal, by law," said B.C. (Barney) Maltby, GSA's regional land sales manager. "If they Fairfax officials decide the cost is too high, it would be our intention to proceed with a public sale."