This work aims to study the effects of temperature and flow velocity on the corrosion behavior of N80 carbon steel in supercritical CO2 environment and explore the corresponding corrosion mechanism by weight loss and electrochemical measurements. Furthermore, the corrosion morphology of N80 carbon steel was observed by scanning electron microscope (SEM) and the composition of corrosion product was analyzed by X-ray diffraction (XRD), respectively. The results indicated that the weight loss corrosion rate was smallest at 40 ℃. Meanwhile, the impedance decreased continuously with the prolongation of time, suggesting that no protective FeCO3 film was formed at 40 ℃. Although increasing temperature enhanced the weight loss corrosion rate in the initial period, the impedance suddenly increased at a certain time at higher temperatures, which indicates the formation of protective FeCO3 film. The higher the temperature, the larger the impedance after corrosion for 24 h, and the denser and more protective corrosion product film. In addition, weight loss corrosion rate increased with the increase of flow velocity. Electrochemical tests also showed that the higher flow velocity, the smaller impedance and the larger corrosion current density. Moreover, SEM surface morphology confirmed that the fluid flow destroyed the compactness of FeCO3 film and then reduced its protective effect for N80 carbon steel substrate. As a conclusion, although increasing temperature aggravates the corrosion of N80 carbon steel in the initial period, it facilitates the formation of protective FeCO3 film. Moreover, the higher the temperature, the denser the FeCO3 product film. The fluid flow destroys the compactness of protective FeCO3 film and thus accelerates the corrosion of N80 carbon steel.