Ultra-sensitive chemiluminescence (CL) analysis is an invaluable tool for detecting the very early stages of polymer oxidation. The oxidation produces such as peroxides that will be integrated in a sample during the oxidation reaction. And their decomposition reaction eliminates a very weak light (chemiluminescence). Therefore, using a high sensitive CL detector, it enables us to detect the early stage of oxidation of polymers. In this research, we tried to detect the oxidation phenomena of the ethylene-vinyl acetate copolymer (EVA) sheet in the electric field. DC around 1KV was charged at room temperature for a few days and measured CL in nitrogen and oxygen. It is the first time detection of EVA oxidation under such a low electric voltage. Using a sensitive CL method, the degradation mechanism by the electric field would be cleared and the R&D period needed to develop a high performance dielectric material will be shortened. And also, by using a highly sensitive CCD camera, oxidation area can be detected from the CL images.