This paper conducted an in-depth study on the internal cavity corrosion of new energy control modules. The paper firstly analyzed the key factors contributing to corrosion in the cooling system cavity of conventional fuel vehicles. Through a plasma concentration orthogonal test, this study simulated the equivalent ion concentration of the cooling medium to identify the influential corrosion factors. Subsequently, by comparing the corrosion rates of aluminum substrates under different corrosive media, this paper demonstrated the applicability of traditional test methods to new energy control systems. A cavity blockage test was designed to verify the functional failure of the cooling system under affected conditions caused by corrosion. Finally, based on the investigation of internal cavity corrosion in new energy control systems, evaluation criteria for conducting internal cavity corrosion test within the company were developed.