Abstract: The effects of hydrostatic pressure and cathodic polarization on stress corrosion of Ti75 alloy are studied by electrochemical polarization test, slow rate test(SSRT), fracture morphology observation and constant deformation stress corrosion test.Resultsshow that hydrostatic pressure has no obvious effect on stress corrosion sensitivity of Ti75 alloy. Under the circumstance of cathodic polarization, the critical stress intensity factor of stress corrosion(K_ISCC) of Ti75 alloy decreases, and the stress corrosion sensitivity increases with the negative shift of the potential. The critical cathodic polarization potential of hydrogen induced stress corrosion is-0.77 V.