To improve the bonding strength and water resistance of starch adhesive, a high properties biomass adhesive was prepared by grafting copolymerization using corn starch as main raw material, itaconic acid and silica sol as graft monomers. The effects of reaction conditions on grafting rate, viscosity, bonding strength and water resistance of starch adhesive were investigated by single factor experiment, the structure and properties of starch adhesive were characterized by FTIR, TGA, XRD and SEM. The results indicated that itaconic acid was successfully grafted onto starch molecules with grafting rate of 6.35% and grafting efficiency of 87.03%, and when the starch mass fraction was 30%, the graft monomer itaconic acid content was 7.5%, reaction temperature was 70 ℃, reaction time was 3.5 h, the modified starch adhesive had the best performance, the water resistance time was 95 h (original starch adhesive was 4 h), the dry and wet strength was 2.28 MPa and 1.52 MPa respectively (original starch adhesive was 0.85 MPa and 0 MPa respectively), which met the national standard for type Ⅲ plywood, the thermal stability of starch adhesive was improved simultaneously.