To investigate the effect of ultrasonic wave on extracting Konjac Glucomannan(KGM) in Konjac refined powder.Free reduced sugar in Konjac refined powder was removed and Konjac refined powder in the aqueous solution was processed by ultrasonic wave and KGM content was measured by spectrophotometry.KGM content in the Konjac refined powder aqueous solution by ultrasonic process at fixed 40 kHz, 100 W, 30-45 min was equal to that by routine method at 4 h; whereas, by 1 h of ultrasonic process, KGM content was significantly enhanced than that by 4 h of routine method(P < 0.01), enhancement rate was 6.5%. Linearity of standard glucose was good (r = 0.9996) in range of 0.2-1.6 mg. The average recovery was 97.8%, RSD of repeatability was 1.27%.Ultrasonic extraction in aqueous solution is a reliable and rapid method that can enhance extraction efficiency of KGM in Konjac refined powder.