Abstract: The effect of calcium phosphate (Ca-P) mineralization on the protease resistance of collagen fibers and its protective effect on the hide grain surface during unhairing were studied. The result shows that: calcium phosphate coating and mineralization can form a micron-level insoluble calcium salt protective layer on the surface of collagen fibers, which improves the heat resistance and protease resistance of collagen fibers, and provides an effective method to protect the hide grain surface during unhairing.