A ball valve structure includes a valve body having a valve chamber therein. A valve ball is accommodated in the valve chamber. The valve ball defines a flow hole therein. Two gaskets are in close contact with two opposite side surfaces of the valve ball, so that the valve ball can rotate around a fixed point in the valve chamber. One side of one of the two gaskets abuts against a washer and a compression spring, so that the gasket is elastically pressed against a surface of the valve ball. A valve stem is connected to the valve ball through the valve body for driving the valve ball to rotate, enabling the flow hole to be opened.