The Charles E. Smith Co., the largest private landholder in Arlington, has lost a major court battle with the county over the assessment of four of the firm's office buildings in Crystal City.

Arlington Circuit Court Judge Paul D. Brown upheld late Wednesday the county's 1980 assessment of almost $57.8 million on four Crystal Mall office buildings. The Marriott Hotel, which is part of the Crystal Mall complex, was not involved in the suit.

Smith and the complex's coowner, the Richmond Land Corp., a subsidiary of the Richmond, Fredericksburg & Potomac Railroad, had contended that the four buildings were worth just under $38 million.

It was the first decision on six lawsuits the developer had filed challenging the county's assessment of its properties. "I think this will set a precedent on some of the issues raised in the other cases," County Attorney Charles G. Flinn said of the case yesterday.

If the county had lost the case, Flinn said, it would have had to refund nearly $222,000 in taxes to the owners. A potential refund of $500,000 is involved in the pending cases.

Neither representatives of the Smith Co. nor Gilbert Hahn Jr., their attorney in the Crystal Mall case, could be reached for comment yesterday. Arlington Assessor James R. Vinson was also unavailable for comment.

The Smith Co. had contended that the value of its buildings should be based on their actual income from rents, and not on market rates. The county argued that the leases were considerably below market value, Flinn said.

The Navy is the primary occupant of three of the Crystal Mall buildings. They are part of a 23-building Smith empire in Arlington.