The invention discloses an adjusting fixture for a machine tool. The adjusting fixture for the machine tool comprises a pedestal; the pedestal is provided with a baffle plate and a support; a clamp block connected through a screw rod is arranged between the support and baffle plate; the other end of the screw rod extends out of the support and is connected with a handle through a bolt; a sewage tank is arranged at four sides of the support and baffle plate; water drain holes are formed in the sewage tank; an adjusting device is arranged at one side of the baffle plate; the adjusting device comprises a bracket, a support plate, a cylinder and an adjusting bolt; an adjusting groove is formed in the middle of the support plate; a movable groove is formed in the middle of the bracket; the support plate is fixed in the adjusting groove through the adjusting bolt and capable of moving up and down in the movable groove; the cylinder is arranged at the front end of the support plate; the piston end of the cylinder is connected with a push rod. The adjusting fixture for the machine tool greatly improves the product stability when processing, enables the processing precision to be guaranteed, improves the product quality and lowers the defective percentage.