Abstract: Microorganism growth can result in biofouling formation and equipment corrosion. In order to solve the biofouling and corrosion problems in recirculating cooling water system, nano ZnO was modified by the silence coupling agent γ-aminopropyltriethoxysilane(KH550). The modified nano ZnO and graphene oxide(GO) were compounded in the dimethylacetamide, and the nano ZnO-GO antibacterial composites were obtained. The waterborne polyurethane(PU) was modified by nano ZnO-GO to get nano ZnO-GO/PU coating composites. The characterizations and antibacterial properties of nano ZnO-GO and the antibacterial properties and physical properties of nano ZnO-GO/PU coating composites were tested and analyzed. The results show that nano ZnO is successfully supported on the surface of GO, and the purity of nano ZnO-GO is high. When the mass fraction of GO is 35wt% and the dosage of nano ZnO-GO is 160 mgL^-1, the antibacterial rate of nano ZnO-GO is 97.16%. When the mass fraction of nano ZnO-GO is 2.33wt% in the coating, the antibacterial rate of nano ZnO-GO/PU composite coating is up to 90.29% and it has 4 H pencil hardness and 93.26% corrosion inhibition performance.