With popular application of fullerene (C-60) and its derivative in functional materials, they have been discharged into water. Therefore, it is urgent to develop an effective and environmentally friendly method for removing C-60 and its derivative from water. However, an efficient method of degradation of C-60 and its derivative in water hasn't been reported. C-60 in water can be oxidized by light to give oxidized C-60 (O-C-60), therefore, degradation of O-C-60 plays a key role in removal of C-60 and its derivative in water. In this paper, O-C-60 was effectively degraded via photo-Fenton method to give carbon dioxide and H2O. The degradation process was monitored by ultraviolet-visible absorption spectroscopy, X-ray diffraction and scanning electron microscopy. Degradation intermediates were determined by Fourier transform infrared spectroscopy, liquid chromatography-tandem mass spectrometry, and elemental analysis. Density functional theory calculations were used to study the mechanism of hydroxyl radical reaction. Based on experimental data and Gaussian calculations, degradation mechanism of O-C-60 in water was proposed.