With the widespread use of lithium iron phosphate batteries in various industries, the amount of waste lithium iron phosphate batteries is also increasing year by year, and if not disposed of in a timely manner, will pollute the environment and waste a lot of metal resources. In the composition of lithium iron phosphate batteries, the cathode has an abundance of elements. The ultrasonic method is a crucial method to recover waste LiFePO4 batteries. It has the following disadvantages, such as the lack of empirical parameters and suitable research equipment. In order to overcome the inefficiency of the LiFePO4 recycling method, the airborne bubble dynamical mechanism of ultrasound in the removal of lithium phosphate cathode material was studied by a high-speed photographic observation and Fluent simulation and the disengagement process. Mainly aimed at the parameters such as action time, power, frequency, and action position in the detachment process were optimized. The recovery efficiency of lithium iron phosphate reached 77.7%, and the recovered lithium iron phosphate powder has good electrochemical properties, with the first charge–discharge ratio of up to 145 (mAh)/g. It is shown that the new disengagement process established in this study was adopted for the recovery of waste LiFePO4.