In this paper, we reported a one-step and facile method to prepare boron carbon oxynitride (BCNO) nanosheet and titanium dioxide (TiO2) loaded BCNO nanocomposites. The BCNO nanosheet not only can widen the absorption range of TiO2 from ultraviolet to visible region, but also increase the photodegradation ability. The TiO2/BCNO nanocomposites have excellent photo-degradation performance on organic dyes. The TiO2-2/BCNO-2 nanocomposite can degrade almost all of methylene blue (MB) and rhodamine B (RhB) during 50 and 300 min under visible light irradiation, respectively. In addition, the photocatalytic mechanism can be explained by the electron transition process between TiO2 and BCNO.