To improve the dispersion of graphene oxide (GO) and form effective synergistic effect between GO and WS2 nanosheets, the layer-by-layer electrostatic assembly method was used to synthesize three-dimensional (3D) reduced graphene oxide/WS2 nanosheet/Mg-doped ZnO nanohybrid (rGOWMZ). The enhancement of photocatalytic activity of a reduced graphene oxide/Mg-doped ZnO composites (rGOMZ) was achieved through introducing WS2 nanoplate, in which the decomposition rate of Rhodamine B (RhB) reached 100% within 5 min. Furthermore, the rGOWMZ hybrids possess better anti-bacterial activity in dark than rGOMZ hybrid. The enhanced sunlight-driven photocatalytic and anti-bacterial activities are mainly attributed to defect and efficient electron-hole separation.