Abstract: The tensile stress corrosion tests of TA31 and TC4ELI alloys at slow strain rates are carried out in dry air and 3.5% NaCl solution, respectively. Combined with the stress-strain curve, the macro and micro structures of the fractured surfaces, the stress corrosion sensitivity of the two alloys are analyzed. The results show that TC4ELI alloy has high stress corrosion sensitivity in 3.5% (w)NaCl solution at 35℃ and the strain rate of 10^-6/s, when the strain rates are 5×10^-7/s and 5×10^-6/s, the stress corrosion sensitivity is low. TA31 alloy has low stress corrosion sensitivity at the above three strain rates. In 3.5% NaCl solution environment, the fracture morphology of TA31 alloy has no obvious change compared with that of air test, while TC4ELI has obvious cleavage surface.