Abstract: The ultrasonic technology was used in insoluble dietary fiber (PIDF) of the potato residue. The effect of PIDF and ultrasonic power, time, temperature and solid-liquid ratio was investigated with single and orthogonal test. The optimum conditions of expansibility were solid-liquid ratio of 1∶10, ultrasonic time of 50min, ultrasonic temperature 70℃, ultrasonic power 70W. Under these conditions, the expansibility was 20.50mL/g. The optimum conditions of water-holding capacity were solid-liquid ratio of 1∶15, ultrasonic time of 40min, ultrasonic temperature 80℃, ultrasonic power 70W. Under these conditions, the water-holding capacity was 14.81g/g.