Constructing p-n junctions is an efficient strategy to resolve the narrow light absorption range and rapid electron-hole recombination problems of single photocatalysts. However, the promotion effect is greatly limited by poor interfacial contact between the p-type and n-type semiconductors. Herein, a facile surface charge-induced electrostatic self-assembly strategy is developed to construct BiOI/TiO2 heterostructures, in which the positively charged TiO2 nanosheets are spontaneously and uniformly assembled on the negatively charged BiOI nanosheets under pronounced electrostatic interaction in formic acid, acetic acid, or aminopropyltriethoxysilane (APTES) aqueous dispersion. Though featuring identical sufficient interfacial contact, BiOI/TiO(2)heterostructures obtained in each dispersion medium, show extraordinary different visible light photocatalytic performance for methyl orange (MO) and phenol. Using multiple characterization techniques, the superior photocatalytic activity of BiOI/TiO2 hetero-structures obtained in formic acid or acetic acid aqueous dispersion, can be ascribed to the enhanced photogenerated charge transportation and separation efficiency, which is attributed to the synergistic effects between the internal electric field induced by the formation of p-n junctions and sufficient interfacial contact. However, due to the remaining APTES goes against the formation of p-n junctions, BiOI/TiO(2)heterostructure obtained in an APTES aqueous dispersion, shows fairly low photogenerated carriers separation efficiency and rather poor visible-light photocatalytic performance. This work may provide a rational and facile strategy to construct highly efficient p-n heterojunction photocatalysts toward environmental purification and solar energy conversion.