Bi3O4Cl/BiOCl (B3O4C/BOC) heterojunction photocatalyst with high visible-light photocatalytic activity was synthesized by one-pot hydrothermal method. The morphology, crystal, structure, optical and photo catalytic property of the synthesized samples were characterized by XRD, SEM, HRTEM, EDX, BET, UV-vis DRS, photocurrent, PL, and etc. The B3O4C/BOC heterojunction photocatalyst exhibited higher photocatalytic activity than pure BiOCl (BOC) and Bi3O4Cl (B3O4C) for the degradation of Orange II under visible light (lambda >= 420 nm). The 0.50B(3)O(4)C/BOC-1 heterojunction exhibited the highest photocatalytic activity and its photocatalytic efficiency was 4.4-fold more than those of pure BOC. In addition, the 0.50B(3)O(4)C/BOC-1 synthesized by one-pot hydrothermal method exhibited higher photocatalytic activity than that prepared by two-step traditional synthesis method. The enhanced photocatalytic activity of the B3O4C/BOC heterostructure photocatalyst was predominantly attributed to the efficient separation of photoinduced electrons and holes. Ultimately, the results also reveal that (OH)-O-center dot and center dot O2- radicals are primarily reactive species in the photocatalytic system, which are the key factors responsible for the nearly complete mineralization of Orange II. (C) 2015 Elsevier B.V. All rights reserved.