Abstract: In order to understand how the environmental factors affect the internal st ructure of the carbon fiberreinforced epoxy resin composites (CFRERC), the relationship between the elect rochemical parameters and the corrosive extent of the composites was investigated by means of the elect rochemical impedance spect roscopy ( EIS) andcyclic voltammograms (CV) curves. The test result s show that the fiber it self does not react with the environment .The ions penet rate into composites and the ions concent ration increases with the immersion time, which leads to thefailure of the composites. The result s indicate that the concent ration and the penet ration process of the ions in thecarbon fiber reinforced epoxy resin composites can be detected by the elect rochemical method.