The present invention provides a method of processing animal skin, comprising the steps of: 1) providing dry animal skin containing 7-38 wt % water; 2) rehydrating and softening the said dry animal skin, and obtaining softened wet skin; 3) mixing the said softened wet skin with water, and grinding the mixture to a slurry; 4) obtaining a solid product through a crosslink of collagen proteins in the said slurry; wherein, rehydrating the said dry animal skin is performed through soaking the dry animal skin in 0-55° C. water till the animal skin contains 40-50 wt % water; and softening the said dry animal skin comprises a step of heating the rehydrated dry animal skin.