Abstract: This present disclosure discloses a plastic pressure hammer for the optical fiber welding machine. The pressure hammer includes a pedestal with a mounting hole, a spring, a main body and a cap. The upper part of the main body said above is installed inside the mounting hole of the pedestal. The said cap is fixedly installed on the upside of the pedestal. The said spring is installed between the cap and the main body of the pressure hammer. At the bottom of the main body, there is a tablet. The main body of the pressure hammer is lineal contact installed inside the mounting hole of the pedestal. At the rear end of the tablet at the bottom of the main body, there is a fixing component adaptive to the V-shape groove of the optical fiber welding machine. This disclosed embodiment improves the defect of big shaking gap of the main body, thus the fiber bounce caused by it is avoided, and the accurate positioning of the main body is realized.