Mg-Al oxides were prepared by facile solvent-free grinding of Mg-Al layered double hydroxide and were used as catalysts for continuous-flow transesterification of dimethyl carbonate and ethanol. The surface and structure properties of the prepared Mg-Al oxides were characterized by X-ray powder diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, and N-2 adsorption-desorption. Moreover, the acid-base properties of the prepared catalysts were characterized using NH3-TPD, CO2-TPD, and pyridine-IR. The Mg-Al oxides prepared using the solvent-free method with a molar ratio of 2.0 (CHT-2-SF) exhibit good catalytic performance, which has medium basic sites, weak acidic sites, and high Brunauer-Emmett-Teller surface areas. A correlation between basicity-acidity and catalytic activity demonstrates that the conversion of ethanol increases with increasing medium basicity and weak acidity of the catalyst. The activity of CHT-2-SF remained almost unchanged after 1800 h on stream.