The apparent enzyme activity of immobilized papain was taken as the index,the effects of ultrasound frequency and power on the kinetics of immobilized papain chemical reaction were investigated. It was found that  the reaction of the immobilized papain decompose casein is consistent with the first-order reaction rate formula. Ultrasonic treatment can significantly reduce the apparent activation energy.The ultrasonic power was 0.05W/cm²,and the ultrasonic frequency was 28,40,50 and 135kHz,the apparent activation energy decreased gradually,and the apparent activation energy was the lowest at 135kHz 0.25W/cm²,it was38.23±0.53kJ/mol.When the ultrasonic frequency was 135kHz and the ultrasonic power is increased from 0.05W/cm² to 0.45W/cm²,the apparent activation energy was the lowest under the ultrasonic condition of 135kHz 0.25W/cm²,which was 32.81.When the ultrasonic power continues to increase,the apparent activation energy shows an upward trend.Under the ultrasound condition of 135kHz 0.25W/cm²,The apparent activation energy was the lowest, which was 32.81±0.09kJ/mol,the apparent activation energy decreased by 52.48% .