Abstract: Took the residue left after extracting the polysaccharide and protein from Hericium erinaceus (HE) as raw material, orthogonal experiment was used to optimize the best process for preparing high-quality Hericium erinaceus dietary fiber (HE-DF₂) by ultrasound-microwave assisted enzymatic method (UMAE), and its structure and physicochemical properties were analyzed. The results showed that when the material particle size was 80 meshes, the enzyme dosage was 3%, the microwave temperature was 55 ℃, the ultrasonic power was 300 W, and the enzymolysis time was 75 min, the SDF content in HE-DF₂ was 12.89%±0.12%, and the oil holding capacity was (2.05±0.01) g/g, cholesterol adsorption capacity was (36.84±0.59) mg/g. Compared with the common Hericium erinaceus dietary fiber (he-df1) prepared with reference to GB 5009.88-2014 determination of dietary fiber in food, the internal structure of HE-DF₂ changed, producing more hydrophilic groups, and its water holding capacity, oil holding capacity, binding water capacity, swelling capacity and cholesterol adsorption capacity were significantly improved, and it satisfied the requirements of high-quality dietary fiber. It showed that UMAE would be beneficial to the improvement of the functional properties of Hericium erinaceus dietary fiber.