The work aims to study anti-corrosion effects of waterborne polyaniline/sepiolite/acrylic emulsion composite coatings on tinplate in sodium chloride medium. Waterborne polyaniline/sepiolite/acrylic emulsion composite anti-corrosive coating was prepared by blending polyaniline/sepiolite composite synthesized in the method of in-situ chemical oxidization polymerization with acrylic emulsion as film-forming material. Structure and morphology of the polyaniline/sepiolite composite were characterized using scanning electron microscopy and EDX. Effects of sepiolite/aniline feed ratio, polyaniline/sepiolite composite consumption and phosphoric acid concentration on corrosion resistance of composite coating were studied using electrochemical impedance-spectra, Tafel curve and copper sulfate dripping test. SEM indicated that polyaniline/sepiolite composite had fibrous structure. Electrochemical test and copper sulfate dripping test showed that polyaniline/sepiolite/acrylic emulsion composite coating exhibited the best anticorrosive performance. Provided with sepiolite/aniline feed ratio of 6:10, polyaniline/sepiolite composite consumption of 0.2% and phosphoric acid concentration of 0.1 mol/L, the corrosion current was 1.013?10?6 A/cm2, corrosion potential was ?0.385 V and polarization resistance was 14 350.8 Ω. Polyaniline/sepiolite/acrylic emulsion composite coating has the best anti-corrosion effect on tinplate provided with sepiolite/aniline feed ratio of 6:10, polyaniline/ sepiolite composite consumption of 0.2% and phosphoric acid concentration of 0.1 mol/L.