TiO2 nanoparticles were loaded on BiOI flower microspheres by solvothermal method. The obtained products were characterized by XRD, FT-IR, XPS, SEM, TEM and UV-VIS-NIR spectrophotometer. Methyl orange (MO) as the target pollutant, the photocatalytic activity of TiO2/BiOI composite was studied under visible light. The results showed that the performance was improved, because TiO2 nanoparticles was contributes to the increase in the specific surface area of the photocatalyst and the heterogeneous structure formed between TiO2 and BiOI could promote photogenerated electrons and hole separation. It was found that the highest photocatalytic activity could be realized when the molar ratio of Ti:Bi was 0.4, and the degradation rate was up to 95%, far higher than that of pure TiO2 nanoparticles and BiOI.