Abstract: For flow wells, the tripping operation difficulties increase due to high oil pressure, and for high solidifying point wells, oil drainage is hard due to paraffin precipitation. In order to solve these problems, the tri-function valve fixed pump is studied. The components of the device include reversing spring, guide tube, king pin, cone, reset spring, and semi-valve ball. Through changing the position of the king pin, the device could achieve the functions of oil drainage, plugging or fixed valve, so the operation of tripping without killing well can be carried out for flow wells, and the paraffin troubled well can drain oil successfully. The field tests on 15 wells indicate that the operation period can be shortened and the damage on formation during well killing can be reduced.