A novel Z-scheme Bi3O4Cl/g-C(3)N(4 )2D/2D heterojunctions were successfully prepared by solid phase calcination method. The Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunctions exhibit outstanding photocatalytic activity for removing the various water contaminant under visible light, such as antibiotic, dye and heavy metal. The enhancement of phototcatalytic performance is ascribed to the interfacial interaction between 2D Bi3O4Cl nanoflakes and 2D g-C3N4 nanosheets, which can enlarge specific surface area and improve separation efficiency of photogenerated electron-hole pairs. To explain the interfacial interaction between Bi3O4Cl and g-C-3 N(4 )in Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunctions, the transmission electron microscopy, X-ray photoelectron spectroscopy and N(2 )adsorption-desorption isotherms measurements were investigated. In addition, the photocatalytic mechanism over Z-scheme Bi3O4Cl/g-C3N4 2D/2D heterojunction is systematically investigated by the calculation, trapping experimental and ESR technology. The present work may provide a promising approach to fabrication of other Z-scheme 2D/2D heterojunction with efficient photocatalytic activity.