A composite of graphene oxide (GO) and titanium (IV) oxide was prepared through a hydrothermal treatment by mixing TiO2 with GO. The GO was obtained by using an improved Hummers' method. The composite (TiO2-GO) only indicated a weak antibacterial effect against Escherichia coli under dark conditions. Upon introduction of silver-based nanomaterials, two new composites viz. GO-TiO2-Ag and GO-TiO2-Ag2S were prepared also through hydrothermal reaction. While both composites exhibit stronger antibacterial activities against E. coli than TiO2-GO in dark, GO-TiO2-Ag composite exhibited higher bactericidal rate (92 %) than GO-TiO2-Ag2S (40 %).