A novel g-C3N4/I-TiO2 composite photocatalyst was successfully designed and prepared by a simple hydrothermal method. The as-synthesized samples were characterized by scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), fourier transform infrared spectroscopy(FT-IR), Brunauer Emmett-Teller(BET) surface area analysis, X-ray photoelectron spectroscopy(XPS), ultraviolet-visible(UV-Vis)spectroscopy. The photocatalytic activities of g-C3N4/I-TiO2 were evaluated by the oxidative degradation of target pollutants such as methyl blue(MB)and rhodamine B(RhB)under visible-lightirradiation(λ＞420nm). XRD results showed that all samples showed only anatse phase structure. 40wt％g-C3N4/I-TiO2 composite photocatalysts samples have aggregate semi-spherical particles.　　Under optimal experimental condition,the 40wt％g-C3N4/I-TiO2 composites photocatalyst exhibited the highest photocatalytic activity.This g-C3N4/I-TiO2 composite photoactive component was incorporated in varying amounts in the g-C3N4,and the resulting composites proved to have improved photoactivity over composites containing the I-TiO2.　　g-CaN4 could directly absorb the photons to induce the excitation of electrons from the highest occupied molecular orbital(HOMO)to the lowest unoccupied molecular orbital (LUMO)of g-C3N4.The excited state electrons could then transfer from the LUMO of g-C3N4to I-TiO2their interracial interaction.This can efficiently inhibit the recombination of photo-generated electrons and holes,and thus significantly improving the photocatalytic performance.This thesis proposes a novel g-C3N4/I-TiO2 compositephotocatalyst that can be used in waste water remediation.g-C3N4/I-TiO2 composite is a material of particular interest due to its chemical and photo-corrosion stability.