The corrosion behavior of Al-5Zn-1Mg-0.02In-0.05Ti-0.1Si (wt %) alloy has been investigated in different pH solutions by cyclic polarization, self-corrosion and scanning electron microscopy. The results show that the alloy undergoes two types of corrosion, including pitting in acidic solutions, relative light pitting in neutral solutions and crystallographic corrosion in alkalinity solutions with a high possibility. The difference of Delta Epsilon= (Epsilon(pit) - Epsilon(cor)) are used as criterion for susceptibility to pitting and the hysteresis loop area as criterion for pitting propagation and repassivation of the alloy. The criterion is discussed. Corrosion morphologies of the alloy are in good agreement with corrosion parameters. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.