HUSY/ZSM⁃5 composite zeolite was synthesized by hydrothermal crystallization, and the structure, acidity and morphology were characterized by X⁃ray diffraction (XRD), N2 adsorption⁃desorption, NH3⁃TPD and scanning electron microscope (SEM) and pyridine infrared(Py⁃FTIR). Epoxidized soybean oil was synthesized using solvent⁃free method, and the catalytic activity of HUSY, HUSY+ZSM⁃5 mechanical mixture and HUSY/ZSM⁃5 for the epoxidation of soybean oil was compared, and the composite zeolite HUSY/ZSM⁃5 showed the best catalytic performance. The optimum conditions for the synthesis of epoxy soybean oil were as follows: 20 mL of soybean oil , 16 mL of 30% hydrogen peroxide, 4.0 mL of acetic acid, 3 g of catalyst. Epoxidized soybean oil with an acid value of 0.46 mg/g and an epoxy value of 5.60% was obtained after reaction at 70 ℃ for 4 h. The product was characterized by FT⁃IR, 1H⁃NMR, and 13C⁃ NMR.