Abstract: Four polyethylene vinyl acetate copolymer(EVA) samples with different contents of vinyl acetate(VA) provided by the same manufacturer are studied under the accelerated aging indoor. The influence of VA contents on the degradation behavior of EVA, such as the yellow index, Fourier Translation Infrared spectroscopy (FTIR), Differential Scanning Calorimetry(DSC) and Thermogravimetric Analysis(TGA), is tested and analyzed.The results show that the ageing-resistance of EVA is positively correlated with VA content in a certain range of 28%~32%, and the higher VA content is, the better ageing-resistance of EVA is. However, when the VA content exceeds 32%, the ageing-resistance of EVA decreases and the aging rate accelerates.