Uniaxial cyclic tensile tests on six groups of ethylene tetrafluoroethylene（ETFE） foil samples of 250μm thick were conducted. After analyzing the stress strain curves based on a newly developed MATLAB program, values of cyclic elastic modulus, yield stress, ratcheting strains and hysteresis loop area were obtained. Furthermore, the equations relating cyclic elastic modulus, ratcheting strain and hysteresis loop area to number of cycles were established. The experimental and analysis results show that change rates of cyclic elastic modulus, ratcheting strains and hysteresis loop area become low with number of cycles and reach approximately stable values at cycle 13, 14, 14.