The Ultrasonic transducer is the core component of the ultrasonic vibration system. The quality of the design of the Ultrasonic transducer is related to the efficiency, stability and life of the welding machine. Most of the piezoelectric ceramic transducers on the market are used, there are many kinds of vibration modes, such as radial vibration mode, longitudinal compound vibration mode, shear vibration mode, thickness vibration mode and so on. When the ultrasonic plastic welding machine works, it needs the high frequency longitudinal vibration to process the plastic workpiece. The welding effect can be obtained by melting the welding layer with high frequency vibration of the upper and lower dies of the workpiece.