Novel g-C3N4/SnS2 van der Waals heterojunctions were fabricated via SnS2 crystals embedded superiorthin g-C3N4 nanosheets for efficient photocatalytic oxidation and reduction activities simultaneously. S-scheme charge migration path was confirmed through test and density functional theory (DFT) calculation. Two dimensional (2D)/2D interfaces, powerful internal electric field (IEF) and band bending effecttogether expedited charge transfer. Photocatalytic removal of organic pollutants and hydrogen evolutionwere employed to evaluate photocatalytic performance. Particularly, the g-C3N4/SnS2 heterojunctionsexhibited excellent 2,4-dichlorophenol (2,4-DCP) photooxidation and Cr(VI) photoreduction activitiesat the same time. 85% of Cr(VI) and 94% of 2,4-DCP were removed in the mixed solution after visible lightirradiation for 2 h (k > 420 nm). The hydrogen evolution rate enhanced to 6.58 times of g-C3N4. DFT simulationmatched with test for narrowed band gap and enhanced IEF (accelerating photogenerated carriertransfer). This work provided new insights for constructing S-scheme multifunctional g-C3N4-basedphotocatalyst.