In this work, the crystallization behaviors, such as degree of crystallinity and crystalline thickness of poly(ε-caprolactone) (PCL) matrix with the incorporation of graphene oxide (GO) and their evolution with time were examined in order to better understand the influences of residual groups of GO on the semi-crystalline polyester. The results showed that the residual strong oxidizing debris on the GO surface could induce the degradation of amorphous parts in PCL matrix. Moreover, the increasing degree of crystallinity and almost constant crystalline thickness implies that oxidative degradation cannot degrade the crystal structure of PCL matrix.