In this study， sea-buckthorn pomace was used as raw material， and the optimum process of ultrasonic assisted enzymatic preparation of dietary fiber from sea-buckthorn pomace was determined by single factor and response surface methodology. The physical and chemical properties， structural properties and functional properties of total dietary fiber (TDF)， soluble dietary fiber (SDF) and insoluble dietary fiber (IDF) were compared. The results showed that the optimum extraction conditions were as follows: solid-liquid ratio 10 ∶ 1 (mL/g)， pH 9.2， enzymatic hydrolysis temperature 48 ℃， enzyme addition 11.40%， ultrasonic power 280 W and ultrasonic time 40 min. Under these conditions， the yield of TDF was 60.74%. In terms of structural characteristics， the three dietary fibers had infrared characteristic absorption peaks of sugars， and there were great differences in micro-structure. For physical and chemical properties and functional properties， SDF exhibited better swelling capacity (19.57 mL/g)， cation exchange capacity (0.50 mmol/g) and adsorption capacity for NO₂- and deoxynivalenol； IDF and TDF had better water holding capacity， oil holding capacity and adsorption capacity for acrylamide and zearalenone. In conclusion， the dietary fiber extracted from sea-buckthorn pomace had good physicochemical properties， structural properties and functional properties. This study will provide reference for improving the utilization rate of sea-buckthorn pomace and studying the function of dietary fiber from sea-buckthorn pomace.