The work aims to improve the corrosion resistance and electrical conductivity of 316L SS in the proton exchange membrane fuel cell (PEMFC) working environment by depositing conductive polyaniline (PANI) film on the surface of 316L stainless steel (SS) and preparing PANI/316L SS composite bipolar plate. The PANI film was electrochemically polymerized on the surface of 316L SS substrate by cyclic voltammetry in an aqueous solution of 0.1 mol/L aniline monomer and 0.2 mol/L H2SO4. The surface morphology was observed by SEM, the structure of PANI functional group was analyzed by FTIR and Raman spectrum, and the element composition and chemical bond state in PANI film were analyzed by XPS. Open circuit potential (OCP), polarization curve and electrochemical impedance spectroscopy (EIS) were used to study the corrosion performance of PANI/316L SS. Four-probe technique was applied to test electrical conductivity of PANI film. From SEM observation results, PANI film was a fibrous accumulation film. The stretching vibration of benzene ring, quinone ring and S==O was found in the infrared spectrum, and the semi-quinone free radical C—N+? was found in the Raman spectrum, confirming that the synthesized PANI had an intermediate oxidation state structure. XPS analysis showed that proton acid doping occurred during polymerization process, and the "counter anion" (SO42-) entered the PANI molecular chain with a doping degree of 3%~4%. Electrochemical test results showed that the OCP of PANI/316L SS was 0.15~0.25 V, the PANI film reduced the corrosion tendency of 316L SS, and the corrosion current density increased with the increase of Cl- concentration. PANI/316L SS system has good corrosion resistance in acidic Cl- containing media, and the formation of protective oxide film Fe2O3 and Cr2O3 at the film/substrate interface improves the corrosion resistance of the PANI/316L SS system. The thickness of PANI film is 146~315 μm and the conductivity is 1.33~8.91 S/cm in preparation conditions.