In order to study the compatibility of 2A14 alloy joint used on propellant tank, stress corrosion mechanism of aluminum alloy was analysized in this paper. The base metal, FSW joint and VPTIG joint of 2A14-T6 aluminum alloy were chosen to make corrosion experimentation with slow strain rate method. The result shows 2A14 aluminum alloy have stress corrosion tendency in 3.5% NaCl solution. And the corrosion resistance of FSW joint is better than VPTIG joint.