Ultrasonic assisted complex enzyme (1.0% alkaline protease and 0.2% high temperature resistant alpha-amylase) was used to extract dietary fiber from milk white colored kidney bean residue after enzymolysis.The effect of ultrasonic conditions on the extraction rate of water-insoluble dietary fiber (IDF) and water-soluble dietary fiber (SDF) was studied.The results showed that the extraction rate of IDF and SDF reached 60.11% and 5.63% respectively, when extracted with 250 W of ultrasonic at 60 ℃ 25 min. There were characteristic absorption peaks in the infrared spectra of DF. The water holding capacity of SDF was 1.828 g/g higher than that of IDF, and the oil holding capacity was 0.69 g/g higher than that of IDF.