Abstract: The stress corrosion cracking(SCC) performance of aluminum alloy Al-3. 88Cu-1. 18Mg-0. 31 Mn in T6,T8 and T3 temper was investigated by using slow strain rate tension testing,optical microscope,scanning electron microscope and transmission electron microscope. The results show that the stress corrosion cracking susceptibility reduces successively at T6,T8 and T3 temper. Stress corrosion has positive correlation with intergranular corrosion,which shows electrochemical corrosion characteristics. Potential difference between grain and grain boundaries determines the stress corrosion cracking susceptibility which is closely related with the microstructure of the grain boundary and its adjacent periphery.