Although Polyester has outstanding wearability, it only has few reacting functional groups in its surface, so protein can not be grafted firmly on polyester fiber surface. Therefore few reports are about grafting protein on polyester fiber’s surface. In this study, the surface of polyester was encased with hydroxide. Then the polyester fibers could be grafted with milk protein by using a synthetic crosslinkages compound. The structure of grafting milk protein polyester fabric was studied by SEM, and the wearability was measured too. Experimental results showed that milk protein could be grafted firmly on polyester through encasing and crosslinking technology. Milk protein could not be washed in the washing process. With the increase of grafted milk protein rate, the whiteness of polyester almost did not change; the cockle elasticity increased firstly, and then decreased, flexural stiffness and hygroscopicity property increased monotonously, moisture permeability increased firstly and decreased subsequently, and antistatic property increased greatly. Encasing hydroxide and grafting milk protein technology is an effective method to produce high functional polyester fabrics.