Abstract: The cold plasma technology is used to treat the surface of PET/epoxy. Based on the analysis of the modified surface of fiber by ESCA, the effects of treatment parameters on the properties of PET/epoxy composite are examined in terms of interlaminar shear strength and transverse tensile strength. The results show that cold plasma treatment can make polarity groups such as oxygen and nitrogen increase on the surface of PET/epoxy, which can improve PET/epoxy impregnation with the resin, and therefore the interfacial property of PET/epoxy composite is improved.