Austenitic stainless steel is widely used in oil exploitation, however, it is faced with severe corrosion because of S and Cl– in the environment. So, its service safely has been widely concerned. In this paper, the influence of Cl– concentrations on the stress corrosion behavior of cold deformation 316L austenitic stainless steel under H2S environment was studied, and the influence of Cl– was discussion. The mechanical behavior of 316L was studied by mechanical method and the elongation loss was used to represent the stress corrosion susceptibility. The pitting potential was characterized by electrochemical method. The diffusion hydrogen content was measured to study the relationship between pitting corrosion and hydrogen. The result show the elongation loss and SCC susceptibility increased with Cl– content. Fracture morphologies changed from cup-shaped equiaxed dimple to cleavage-type brittle fracture. Kinetic potential polarization experiment showed that the pitting potential gradually decreased to 0.0228 V and the sample was more prone to pitting as the increasing of Cl– concentration. Hydrogen content showed that pitting increased hydrogen content in the metal matrix. Cl– has an important influence on the stress corrosion behavior of 316L austenitic stainless steel in H2S environment. SCC susceptibility increases with Cl– concentration. It may be due that Cl– damaged the passivation film on the metal surface and resulted in pitting pits, where the crack nucleates and expands. At the same time, pitting also increased hydrogen content in the metal matrix and then improved the stress corrosion cracking susceptibility.