It is commonly considered that the morphology and interface of semiconductor-reduced graphene oxide (rGO) composite photocatalysts play a crucial role in determining their photocatalyzing performance. Herein, we report on the design and synthesis of BiVO4-rGO nanocomposites with efficient interfacial contact by self-assembly of positively charged amorphous BiVO4 powders with negatively charged graphene oxide (GO), followed by a one-step GO reduction and BiVO4 crystallization via hydrothermal treatment. The as-prepared BiVO4-rGO nanocomposites exhibit high visible light photocatalytic efficiency for the degradation of model dyes, and are significantly superior to bare crystalline BiVO4 and BiVO4-rGO-U that is hydrothermally synthesized using the mixture of GO nanosheets and BiVO4 powders without modification of surface charge. Using multiple characterization techniques, we found that the enhanced photocatalytic performance of BiVO4-rGO arises from the synergistic effects between the microscopic crystal structure of BiVO4 with smaller particle size and more sufficient interfacial interaction between BiVO4 and graphene sheets, leading to increased photocatalytic reaction sites, extended photoresponding range, enhanced photogenerated charge separation, and transportation efficiency. This work may provide a rational and convenient strategy to construct highly efficient semiconductor-rGO nanocomposite photocatalysts with well-contacted interface toward environmental purification and solar energy conversion.