An effect of Cl-concentration on the stress corrosion cracking (SCC) behavior of 13Cr stainless steel was investigated by employing electrochemical measurements and the slow strain rate tensile tests· These tests were conducted in various solutions with different concentrations of NaCl at 90 ℃ under 3 MPa CO2 with 3 MPa N2· The results indicate that the passive film of the specimen formed in the 10％ NaCl solution has the best protective effect on the matrix.The SCC susceptibility does not increase with increasing the chloride ion concentration,the lowest SCC susceptibility occurs when the NaCl concentration is 10％,and the specimens show higher SCC susceptibility in the 5％ NaCl and 20％ NaCl solutions.