Mg-doped TiO2mesoporous nanomaterial with high-efficiency solar photoelectric conversion was successfully prepared by a solid-state reaction using cetyltrimethyl ammonium bromide as a template agent. As-prepared Mg-TiO2nanomaterials are characterized with XRD、SEM, UV-Vis, XPS, BET and Raman spectroscopy. It was found that magnesium as Mg2+incorporates into the framework of TiO2by isomorphous replacement with content of 2.36%. The Mg-TiO2nanoparticles are anatase phase with particle size of 10-24nm. The rod-like nanoparticles have specific surface area of 104.5m2/g and pore-diameter distribution centre of 5.1 nm. The surface of Mg-TiO2material with stretching vibrational peak at 1105cm−1is assignable to the Mg-O-Ti bond. Furthermore, the UV–vis displays that the absorption region of mesoporous Mg-TiO2powder shifts to 405nm, and the absorption intensity of the visible-light region is enhancement. At 20oC, pH = 6.8,c0= 50 mg/L, within 150 min, the rule of pseudo-second-order reaction and the degradation rate of thiophanate methyl of 57% and 91.8% corresponding visible-light irradiation and ultraviolet irradiation are obtained for the Mg-TiO2nanomaterial. But it is poor to photodegradation of thiophanate methyl for P25-TiO2, and it keeps to the rule of pseudo-first-order reaction.