Abstract: The ultrasonic-microwave synergistic method was used to extract the soluble dietary fiber from seabuckthorn peel residue. The effects of mass fraction of citric acid,solid-liquid ratio,microwave power and extraction time on the extraction rate of soluble dietary fiber in seabuckthorn peel residue were studied by single factor experiment,and the optimal extraction process of soluble dietary fiber in seabuckthorn peel residue was further optimized by box-behnken method. The results showed that under the condition of citric acid mass fraction of 3%,solid-liquid ratio of 1:16 g/mL,microwave power of 620 W and extraction time of 60 min,the extraction efficiency of soluble dietary fiber in seabuckthorn peel residue was the best,and the extraction rate was 11.07%±0.26%,and the error with the model predicted value of 10.83% was 2.22%. The water-holding capacity,oil-holding capacity and expansion capacity of the soluble dietary fiber in the prepared seabuckthorn peel residue were 8.02 g/g,4.19 g/g and 3.82 mL/g,respectively. Ultrasonic-microwave synergy is an effective method for extracting soluble dietary fiber from seabuckthorn peel residue.