Abstract: Aiming at the corrosion perforation problem of N80 oil casing steel in Su 77 and Zhao 51 blocks, the effect mechanisms and anti-corrosion effects of RX-204B and IMC-80BH corrosion inhibitors was studied by high temperature and high pressure simulation test and electrochemical polarization curve method. The surface morphology of the samples before and after the removal of corrosion products was observed by SEM.The composition of the corrosion products were studied by energy spectrum analyzer. The results show that both corrosion inhibitors are anode-controlled corrosion inhibitors with adsorption membranes. Due to different composition, the mechanism of action of functional groups is different. There are some differences in the polarization curves of the two corrosion inhibitors at different concentrations. Finally, the corrosion mechanism and optimal filling concentration of the two corrosion inhibitors are explicit.In addition, the optimal anti-corrosion process for SU 77 and ZHAO 51 block gas well appears.