The impact of temperature on CO2 corrosion was investigated by weight loss, in situ electrochemical measurements, and characterization of corrosion product film. The results showed that with the increase of temperature, corrosion rate decreased remarkably, which can be ascribed to different product films formed on metal surfaces. As the temperature increased, the growth tendency of FeCO3 crystals on the (012) plane becam more pronounced, ultimately forming a dense film. Synchrotron-based computed laminography analysis proved the porosity of products decreased with the rising of temperature. The relationship between the microstructure of product film and corrosion rate has also been proposed.