In order to improve the wet shear strength of soy protein based adhesive,the authors used two resins as a cross-linking agent to modify soy protein based adhesive.The modified soy protein-based adhesive was then used to make plywood samples.The results showed that when processed at 160 ℃,1.5 MPa,2 min/mm,and 380 g/m2 glue spread,the plywood wet shear strength met the National Standard GB/T 9846-2004 requirement for I-level plywood.The cross-linking agent also dramatically improved the bonding performance of the plywood samples in boiling water.