Abstract: A new finite element method was proposed,which was used to identify the cause of product failure due to vibration in ultrasonic welding.According to the principle of welding machine,the complex welding system was simplified.For the simulation,the loading method and transforming mechanism of energy transmission was given and verified by temperature distribution in the joint calculated by the thermal mechanica coupled model.Based on the idea proposed in this paper,a 3D finite element model was established for analyzing the vibration of cell phone battery during ultrasonic welding,and experiments proved its favorable effect.