Abstract: Cotton fabrics were treated with maleic acid/itaconic acid(MA/IA) or MA alone by an in-situ polymerization-crosslinking method to improve their wrinkle resistance.The relationship between tensile strength and wrinkle recovery angle or amount of ester-linkages was determined.The factor ofBSLFwas proposed to indicate the extent of strength loss for a treated fabric.The results of linear regression show that a high degree of linear correlation exists between the amount of ester-linkages and the tensile strength retention(or the wrinkle recovery angle) of the treated fabrics,and so does it between the tensile strength and the wrinkle recovery angle of the fabrics.The mathematic relationship between the line slope andBSLFwas deduced.Compared with the line slope,theBSLFfactor can be obtained conveniently,so it may be an alternative to indicate the extent of strength loss for a particular wrinkle-free finishing system.