The work aims to study the corrosion behavior of vehicle organic coating in the environment of coastal areas polluted by the acid rain. The corrosion failure process of metal paint coating in the acid salt spray environment was studied in electrochemical impedance spectroscopy (EIS) method. The change law of EIS features and the coating capacitance were analyzed. The intermediate frequency phase angle (θ10) and impedance magnitude (|Z|10) were used to evaluate the protective performance of the coating. The corrosion failure process of metal paint coating had gone through three stages: the undamaged coating, the reduced protective performance of coating and the coating failure. The coating capacitance gradually increased with the increasing corrosion time. When θ10＜28.78° and |Z|10＜1.78×107 Ω•cm2, the coating basically lost its ability to protect against the corrosion. With θ10 and |Z|10, the corrosion protection performance of metal paint coating in acid salt spray environment can be effectively evaluated, so as to provide the technical support for the corrosion prevention of military vehicles in the coastal areas.