tThe visible-light-driven (VLD) photocatalytic activity of graphene oxide–zinc oxide (GO–ZnO) compositeprepared by a simple hydrothermal method was evaluated toward the inactivation of Escherichia coli K-12. The results showed that GO–ZnO composite had excellent VLD photocatalytic bacterial inactivationactivity, comparing with those of ZnO and GO, which was attributed to the strong interaction between ZnOand GO in the composite. Accordingly, an interaction induced VLD photocatalytic inactivation mechanismof the strong interaction of GO with ZnO within the GO–ZnO composite was proposed. GO served as aphotosensitizer and facilitated the charge separation and transfer, thus boosted the massive productionof reactive oxygen species such as•OHbulk, which was identified as the major reactive species fromconduction band of ZnO, and resulted in a remarkable enhancement of bacterial inactivation efficiency.Moreover, GO–ZnO composite showed obviously superior photocatalytic bacterial inactivation within10 min under natural solar light irradiation, indicating that GO–ZnO composite has great potential inwastewater treatment and environmental protection.