In order to master the electrochemical characteristics of aviation CFRP in the aging process, and accurately obtain the equivalent conversion coefficient of the metal in CFRP/metal coupling, CF8611/AC531 composite and 7B04 aluminum alloy commonly used in aircraft were studied under the background of marine environment. The accelerated aging test and polarization test of the CFRP in different electrolytes were carried out, and optical microscope, SEM and FTIR were used at the same time to observe the change of its performance during aging time. Under the premise of fully considering the galvanic effect corrosion acceleration, the equivalent conversion coefficient calculation method was improved, and the galvanic current of CFRP/7B04 couple was obtained based on the galvanic corrosion model, and the corresponding conversion coefficient was calculated. The results show that with the aging process, the epoxy resin on the surface of CFRP decomposes gradually, which makes the carbon fiber exposed and the cathode property is enhanced. When the CFRP is polarized in the electrolyte containing Cu2+, the bare area of carbon fiber will form the aggregation of Cu. The ratio of the bare area remains about 0.9 after 420 h, which means that the cathode property reaches a relatively stable state. The relationship between the self-corrosion current density and the exposed area of carbon fiber is obtained, and the aging mechanism and cathodic reaction mechanism are defined by dividing the surface-active cathode area and the inert cathode region. The corrosion parameters of CFRP/7B04 couple and the improved equivalent conversion coefficient are obtained. The cathode property of this type of composite is very well, and the active cathode area is the important source of its cathode property, so direct contact with metal should be avoided. The influence of galvanic effect must be considered in the design of accelerated corrosion environmental spectrum of structural parts in laboratory, so as to improve the accuracy and applicability of environmental spectrum.