Mesoporous Cu2O (MP-Cu2O) microspheres were prepared via a facile template-free hydrothermal synthesis in the open system, in which copper acetate was used as the copper precursor and glucose as a reducing agent. The synthesis conditions and catalytic property of MP-Cu2O for dimethyldichlorosilane synthesis via the Rochow reaction were investigated, and the formation mechanism of MP-Cu2O microspheres was proposed. The samples were characterized by nitrogen adsorption, X-ray diffraction, temperature-programmed reduction, thermogravimetric analysis, transmission electron microscopy, and scanning electron microscopy. It was found that the synthesis conditions such as reaction temperature, time, and reactant amount added have a significant effect on the morphology and pore structure of MP-Cu2O microspheres, and MP-Cu2O microspheres were formed through assembly of Cu2O nanoparticles. MP-Cu2O microspheres with a surface area of 65.8 m(2)/g, pore size of 26.7 nm, and a diameter of 400-700 nm were obtained under the optimized condition. As compared to the nonporous Cu2O microspheres, MP-Cu2O microspheres showed a better catalytic performance in dimethyldichlorosilane synthesis due to their developed pore structure and high surface area, which allow larger contact interface among the reaction gas, solid catalyst, and the solid reactant, together with enhanced mass transport. The work would be helpful for developing novel structured copper catalysts for organosilane synthesis and for understanding the catalytic mechanism.