Spray pyrolysis was used to prepare catalysts containing magnesium with mesopores. MgO-SiO2, MgOAl2O3, and MgO-SiO2-Al2O3 catalysts were synthesized using cetyltrimethylammonium bromide (CTAB) as a templating agent. The characteristics of the catalysts were examined by N2 adsorption, XRD, XRF and the temperature-programmed desorption of carbon dioxide. The MgO-SiO2 catalyst has well-developed mesopores, a large surface area and well dispersed magnesium oxide. The basic sites on the MgO-SiO2 catalyst were much stronger than those on the MgO-SiO2-Al2O3 and MgO-Al2O3 catalysts. The catalytic performance for the decomposition of dibenzothiophene sulfone (DBTS) to biphenyl and sulfur dioxide gas was examined in a fixed-bed reactor. The MgO-SiO2 catalyst has the highest activity in the cracking of DBTS, which was attributed to the strong basicity due to the dispersed effect of magnesium oxide. Compared to the MgO catalyst, the mesoporous MgO-SiO2 solid base can improve significantly the catalytic efficiency for the removal of sulfur dioxide from dibenzothiophene sulfone.