Abstract: In order to alleviate the DC interference of subway, the combination of sacrificial anodes and polarized electric drainagers is often used in urban gas pipelines. The service performance of two polarized electric drainagers, Schottky diode+capacitor+surge protector type (No.1) and metal oxide semiconductor field effect transistor (MOSFET)+capacitor+surge protector type (No.2), was compared using a combination of laboratory testing and field testing. The effect and mechanism of the two polarized electric drainager under the dynamic DC interference and AC interference were obtained through field tests. The results show that the polarized electric drainager No.1 had a better drainage effect than that of the polarized electric drainager No.2, but the polarized electric drainager No.2 had better reverse insulation performance than that of the polarized electric drainager No.1. Both polarized electric drainagers connecting with drainage bed had a mitigating effect on pipeline DC interference and AC interference, and the polarized electric drainager No.2 had a better mitigating effect than that of No.1.