In order to probe into the effects of ultrasound in different parameters on amylase activity, coarse amylase of rice was purified with diethylaminoethyl cellulose chromatography after being salted out with (NH_4)_2SO_4. Two single protein peaks were separated with gradient elution. The second protein component showed quite high amylase activity and the activity peak inosculated with the protein peak. The ingredient having the highest activity in the second protein peak was used to process polyacrylamide gel electrophoresis. The results showed that there were less ingredients in the purified sample than in the coarse sample. Ultrasound treatment with suitable parameters could increase the enzyme activity by 9.09%-33.09%.