Abstract: The corrosion behavior of G105 drill pipe was investigated by slow strain rate tension (SSRT) and electrochemical test in HAc/NaAc buffer solution with different hydrogen ion concentrations. The fracture morphology and the mechanism of stress corrosion of SSRT sample were studied.The results show that with the increase of hydrogen ion concentration, the stress corrosion sensitivity and corrosion current density of G105 drill pipe increased gradually. The fracture morphology exhibited brittle characteristic and the main crack showed obvious branch cracks. The mechanism of stress corrosion was anodic dissolution, a part of hydrogen atoms in the acidic solution entered the cracks and accelerated the process of stress corrosion cracking.