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The critical pitting temperature (CPT) is considered an indicator for assessing the pitting sensitivity of stainless steels. When the stainless steel is below a certain temperature, its corrosion current density shows no significant change, indicating that the passivation film on the surface of the sample remains intact within this temperature range; this region is known as the temperature-passivation region. When this temperature is exceeded, the corrosion current density of stainless steel increases sharply, indicating that the passivation film on its surface is broken and pitting begins to form. The effect of temperature on pitting typically manifests in two opposing aspects: raising the temperature can facilitate the diffusion of ions within the pores, thereby suppressing the pitting process to some extent; however, it also accelerates the reaction kinetics, promoting the development of pitting. The competition between the two leads to a transition of pitting between a metastable and a stable state. In oil and gas field environments, due to the complex internal conditions, stainless steel is often exposed to corrosive media with varying temperatures; therefore, studying temperature changes is of great significance for understanding the pitting behavior of stainless steel in such environments. Temperature affects the thermodynamic state and kinetic processes of 304 stainless steel. The higher the temperature, the more difficult it is to establish and maintain the passive state of the metal, which leads to increased Cl- activity; these ions adsorb on the surface of the passivation film, thereby increasing the number of active areas on the film ； At the same time, the stability and repair capacity of the passivation film are low, which reduces the pitting resistance of stainless steel ； The increase in passivation current also indicates that stainless steel exhibits better passivation properties at low temperatures. Whether or not CO2 is present in the corrosive medium, the self-corrosion current density of stainless steel increases gradually as the temperature rises, while the pitting potential decreases, resulting in more pronounced corrosion. In the high-temperature and high-pressure corrosive environment of simulated oil fields, the average corrosion rate of stainless steel increases as the temperature rises; when the temperature reaches 150°C, the average corrosion rate reaches its maximum value of approximately 0.25 mm/a. When the temperature is below 150°C, Cr is converted to Cr(OH)3, and Cr(OH)3 further dehydrates to form Cr2O3; therefore, the main component of the corrosion products is Cr2O3. When the temperature reached 200°C, in addition to Cr2O3, iron compounds such as Fe3C and FeCO3 were also detected in the corrosion products. The corrosion products of stainless steel in similar environments change with temperature. This indicates that as the temperature rises, the corrosion mechanism of stainless steel begins to change; as a result, the corrosion morphology and corrosion products vary at different temperatures.