In this paper, mesoporous nitrogen-doped TiO2 microspheres were prepared by a template-free solvothermalmethod. The nitrogen-doped TiO2 mesoporous spheres show higher visible-light photocatalytic activity thanthe undoped TiO2. The dual role of urea helps the formation of a mesoporous structure and the doping ofnitrogen into TiO2 to be completed simultaneously during the solvothermal process. The amount of ureashows the crucial effect on the mesoporous structure and nitrogen doping in TiO2.