Abstract: Based on the investigation of casing damage wells in an oilfield, the internal and external corrosion environment and corrosion reasons of the casing were clarified by analyzing the composition of produced water and corrosion products. The corrosion resistance of the casing material in use was evaluated by chemical composition analysis and corrosion rate test under simulated working conditions. The effective protection distances of built-in and external sacrificial anodes for casing in different environments were calculated by finite element simulation method. The corrosion inhibition performance of the solid corrosion inhibitor in use was evaluated by the release rate and inhibition rate test. Finally, some improvement suggestions for corrosion protection measures were put forward according to the evaluation results.