Abstract: Novel mulriple polymer polyaniline/Bi₂SnTiO₇ was synthesized by chemical oxidation in-situ polymerization method and sol-gel method for the first time. The structural and photocatalytic properties of novel polyaniline/Bi₂SnTiO₇ have been characterized by X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray spectrometry. The photocatalytic degradation of methylene blue was realized under visible light irradiation with novel polyaniline/Bi₂SnTiO₇ as catalyst. The results showed that novel polyaniline/Bi₂SnTiO₇ owned higher catalytic activity compared with Bi₂SnTiO₇ or pure TiO₂ or N-doped TiO₂ for photocatalytic degradation of methylene blue under visible light irradiation. The photocatalytic degradation of methylene blue with novel polyaniline/Bi₂SnTiO₇ or N-doped TiO₂ as catalyst followed the first-order reaction kinetics, and the first-order rate constant was 0.01350 or 0.00333 min-1. After visible light irradiation for 220 min with novel polyaniline/Bi₂SnTiO₇ as catalyst, complete removal and mineralization of methylene blue was observed. The reduction of the total organic carbon, the formation of inorganic products, SO₄^2- and NO₃^-, and the evolution of CO₂ revealed the continuous mineralization of methylene blue during the photocatalytic process. The possible photocatalytic degradation pathway of methylene blue was obtained under visible light irradiation. Novel mulriple polymer polyaniline/Bi₂SnTiO₇/(visible light) photocatalysis system was found to be suitable for textile industry wastewater treatment and could be used to solve other environmental chemical pollution problems.