Soy protein, as well as gelatin and a blend of them were selected as protein raw material to prepare coating solutions for corrugated carton. Poly ethylene glycol was used as a plasticizer, and the soy protein was used without treatment. The effect of pH of soy protein usingNaOH onmechanical properties of corrugated carton was studied. It was found that the soy protein coating solution increases the thickness of carton more than gelatin coating solution. Blending of gelatin with soy protein in a ratio of 1:1 reduces the defects of soy protein and improves the physical properties of the coated carton. Microstructure, water uptake, water permeability and dye uptake of the coated carton were also studied.