Abstract: A mounting tool for an axle lock nut comprises a pole, an end of the pole is a knocking end and the other end is provided with a suppressing unit and a retaining unit, the retaining unit is in adjacent to a side of the suppressing unit and the retaining unit is protruded out of a tail end of the suppressing unit. The mounting tool is used to position the axle lock nut on an automobile axle and to increase the reliability of operation for mounting the axle lock nut on the automobile axle.