Abstract: The corrosion behavior and mechanism of carbon fiber coupled carbon steel in drainage pipe system were studied through anodic polarization curve test, impedance test and corrosion weight-loss test. The results showed that the corrosion sensitivity of carbon steel in simulated pore solution increased after coupling carbon fiber, and the higher the concentration of chloride ion, the bigger the corrosion tendency; the corrosion rate of the simulated pore solution from high to low was 0.4% carbon fiber >0.2% carbon fiber > carbon steel; that by controlling the added amount of carbon fiber and reducing the concentration of chloride ion in the medium could improve corrosion resistance of reinforced concrete pile.