Abstract: The ultrasonic technology was applied to desizing of the cotton fabric with hot water,alkali and amylases,and the desizing percentage of both PVA and starch of the cotton fabrics desized under the ultrasonic wave was determined and compared with that desized under normal conditions.The results indicated that the ultrasonic wave have obvious effect to the desizing with amylases.The optimized desizing conditions with amylases under ultrasonic wave were also confirmed: amylases 5 g/L,temperature(50 ℃,)time 10～15 min.