Under-deposit corrosion (UDC) is one of the important reasons for the failure of oil and gas pipelines. The corrosion environment under the scale layer is different from the area covered by the non-scale layer, which may cause serious local corrosion and even cause pipe perforation. Aiming at the inorganic scale layer in CO2 environment, the research progress of carbon steel under-deposit corrosion in oil and gas pipelines is reviewed. The mechanism, influencing factors, and control methods of under-deposit corrosion are briefly described.