It is used with water -oil repellent to improve the latter’s durable performance. It forms a robust cross-linked network on fabrics’ surface, effectively blocking the penetration of water. After using it, initial waterproofness of water-oil repellent is greatly improved, making the processed fabrics more wash-durable. Besides, through building crosslinking bonds between fiber molecules, crosslinking agent remarkably improves waterproofness, colorfastness, abrasion resistance, tensile strength and tear strength of the treated fabrics. For instance, while processing high-strength industrial textiles, the proper use of crosslinking agent can greatly extend their service life.