Abstract: Aiming at protective problem of aluminum alloy ship and gun equipment component used in the case of hot and humid marine environment conditions, the corrosion behavior was studied using the imitated marine environment coupling test method, the aluminum alloy fracture morphologies, corrosion morphologies and microstructure morphologies were analyzed using SEM and OM, the corrosion area and fracture surface element component were analyzed using energy spectrum analysis method.The results show that the cracks of ZL205A imitated parts originate in the intercrystalline corrosion area, and continuously extend and expand under the coupling action of corrosion and stress, which finally leads to the cracking of casting aluminum alloy parts.The corrosion type of ZL205A casting aluminum alloy is stress corrosion.