The utility model discloses an assembling and drilling tool for a grounding switch, and the tool comprises a pedestal fixing device and a driving transmission shaft positioning device. The pedestal fixing device comprises a vertical maintaining structure which is used for maintaining the pedestal of the grounding switch to be vertical and facilitates the drilling. The pedestal fixing device also comprises a balance plate positioning device which is used for positioning a balance plate and enabling the balance plate to form an inclined angle along with a vertical line. The driving transmission shaft positioning device comprises an adjusting block which is connected to a driving transmission shaft. The adjusting block is provided with adjusting screw rods in bolt holes at two sides of the driving transmission shaft in a rotary manner. The adjusting screw rods are adjusted so as to enable the distances from two ends of the adjusting block to a vertical plate of the grounding switch to be equal, thereby positioning the peripheral position of the driving transmission shaft. The tool can guarantee that the positions and angles of the balance plate and the transmission shaft meet the requirements of design, and is more accurate and accurate in drilling. Moreover, the tool is simple, is reasonable in design, and eliminates the defects in assembling and drilling of the grounding switch.