A novel metal-free oxygen-doped graphitic carbon nitride (O-g-C3N4) was synthesized by the pre-treatment of bulk graphitic carbon nitride (g-C3N4) with hydrogen peroxide (H2O2), and combined with high-temperature calcination treatment. The obtained 2-O-g-C3N4 catalyst exhibits high activity in visible light photocatalytic degradation of bisphenol A (BPA) with a mineralization rate as high as 62.3%. According to the characterization results of X-ray diffraction, transmission electron microscopy, UV-visible spectroscopy, Brunauer-Emmett-Teller and photoluminescence spectroscopy analyses, the markedly higher visible-light-driven oxidation activity of 2-O-g-C3N4 is attributed to the larger specific surface area, wider range of light responses and low charge recombination rate. Moreover, the trapping experiment shows that superoxide radicals (•O2 -) are the dominant active species in the BPA decomposition process over 2-O-g-C3N4. This study presents a simple and environment-friendly method to synthesise oxygen-doped graphitic carbon nitride.