Abstract: The self-made simulation device was used to simulate pigging referring to oilfield technological process. The influence of pigging and inhibitor injection on the corrosion of 20^# steel in simulated liquid of pipeline was analyzed by weight-loss method and corrosion electrochemical method. The results show that the amount of liquid and solid deposit on the surface of 20^# steel sample are reduced after pigging with a 3% interference cup pig, and the corrosion rate is significantly reduced. When the corrosion inhibitor is added into the simulated solution or the sample is prefilmed with inhibitor, the inhibitor molecules will act on the surface of carbon steel to form a layer of corrosion inhibition film, which effectively hinders the direct contact between the sample and corrosion medium. After pigging combined with corrosion inhibitor pre-film, the corrosion rate is reduced to 0.029 mm/a, which has a good protection effect on carbon steel.