Abstract: The effect of cathodic polarization potential on stress corrosion cracking (SCC) susceptibility of titanium alloys Ti80, Ti75 and Ti31 in simulated deep sea environment was studied by electrochemical test and slow strain rate test (SSRT). The results show that the SCC susceptibility of Ti80, Ti75 and Ti31 all had a increasing tendency when the cathodic polarization potential shifted negatively. The most negative cathodic polarization potentials (relative to Ag/AgCl electrode) of Ti80, Ti75 and Ti31 without obvious stress corrosion tendency were -0.77 V, -0.73 V and -0.73 V, respectively, in simulated deep sea environment.