The work aims to modify the soybean protein with epoxy resin to prepare environment-friendly soybean protein-epoxy composite adhesive, so as to improve the water resistance and low adhesive strength of soybean adhesives, and effectively utilize the excellent adhesive strength, corrosion resistance and mechanical strength of epoxy resin adhesives. The solid content, viscosity and bonding strength of composite adhesives were analyzed and studied by orthogonal test. The effects of soybean protein quality, epoxy resin quality and maleic anhydride quality on the adhesive properties were investigated. When the optimum technological parameters of 20 g soybean protein, 20 g epoxy resin and 4 g maleic anhydride were obtained, the adhesive strength reached 1.60 MPa, meeting national Ⅱ kind of plywood (GB/T 9846—2004) requirements. The adhesive strength of soybean protein adhesives is improved significantly under the optimum conditions, and the modified effect of epoxy resin on soybean protein is better.