Abstract: The water-chemical environment, temperature, and cold work have an important influence on the stress corrosion cracking (SCC) of the primary loop pipe of pressurized water reactor (PWR). Therefore, it is of great significance to study the influence of different factors on the SCC of the primary loop pipe. The effect of temperature, water-chemical environment, and cold work on stress corrosion crack growth rate (SCCGR) of 321 stainless steel (321SS) with experiment of constant stress field intensity factor was studied. And the synergistic effect of these factors on SCCGR of 321SS was also studied. It is found that with the increase of temperature, the SCCGR of the materials increases first and then decreases in the B-Li and B-Li-O₂ environments. But SCCGR increases with the temperature in the B-Li-O₂-Cl^- environment. Dissolved oxygen (DO) and Cl^- have synergistic effect on the SCCGR, and the effect of O₂ on SCCGR is greater than that of Cl-. In B-Li environment, cold work has little effect on SCCGR of the material. However, in corrosive environments (B-Li-O₂, B-Li-O₂-Cl^-), cold work has a greater influence on SCCGR of materials, and the stronger the corrosive environment, the greater the impact of cold work on SCCGR. The experimental results show that water-chemical environment, temperature, and cold work have synergistic effect on the stress corrosion crack growth of 321SS.