A collagen based adhesive was prepared by using polyurethane prepolymer as the cross-linking agent, and collagen hydrolyzate derived from tanned leather wastes as the raw material. Five different wood adhesive formulations were obtained through controlling the molar rate of the amino group and the isocyanate group. The properties and structure were measured by solid content, water resistance and modern instrument characterization. The relative molecular mass of modified adhesives was obviously increased, the crystallinity was obviously reduced and the thermal stability is improved significantly after modification. The results indicated that the water resistance was the best when the molar rate was 1:1 and the wet shear strength could reach to 1.08MPa(≥0.7MPa), which met the requirement of GB/T9846.3-2004. The solid content (38.16%) and the stability of Formulation 2 adhesive were also the optimal.