Abstract: In this article, the color differential and tensile strength of polycarbonate(PC) after different weathering stage during one year in Qionghai, Ruoqiang and Hailaer were tested, and the FTIR characteristic indexes were also calculated. On this basis，the mechanisms of PC weathering in different location and Pearson correlation coefficients between PC properties and IR feature indexes have been studied. The results show that when exposed in Qionghai, the PC will conduct both Fries-rearrangement and photo-oxidation reaction, it may mainly conduct photo-oxidation reaction in Ruoqiang and Hailaer. All these two reactions will cause color change in the, other hand, only Fries-rearrangement reaction cause tensile strength descend.

Key words: polycarbonate, outdoor exposure, infrared characteristic index, photo-oxidation, Fries-rearrangement reaction, Pearson correlation coefficient