In this study, silver decorated graphene oxide (Ag/GO) composite was fabricated through a reduction process in the presence of potassium borohydride solution. Subsequently, physicochemical properties of the resulting Ag/GO composite were studied by scanning electron microscope, X-ray diffraction, Raman spectra, Fourier transformation infrared spectroscopy and UV-visible diffuse reflectance spectrum. Results indicated that Ag species existed in the form of Ag0, which greatly facilitated the visible light absorbance ability. Furthermore, the performance of Ag/GO was evaluated by PC inactiviation of Escherichia coli under Xenon lamp illumination. It was found that Ag/GO sample could kill the Escherichia coli within 60 min illumination by the non-selective attack of ⋅OH radicals. This study provides a novel and facile strategy to fabricate high-efficient catalyst to kill the bacteria in drinking water treatment.