Abstract: If hydrogen sulfide content in LPG is on the high side, LPG tank will be corroded. Three factors for wet hydrogen sulfideenvironment and sulfide stress corrosion cracking are analyzed and indicating characteristics of magnetic particle indication influorescent magnetic powder detection and detection steps are introduced. It is pointed out that shallower and slighter cracks, which are unavailable with magnetic powder detection method, can be found out in metallographic inspection, Based on analysis of tank stress corrosion cases, it is indicated that preventing against stress corrosion of LPG tank should eliminate the factors ofenvironment, mechanics and metallurgy. Relative preventive measures are put forward simultaneously.