Mg-Al-O-t-Bu hydrotalcite was synthesized and characterized by XRD, FT-IR and TGA-DTA. It was proved to be an active heterogeneous catalyst for the transesterification of dimethyl carbonate (DMC) with ethanol. When the reaction was carried out over Mg-Al-O-t-Bu hydrotalcite at 80 degrees C, 7 h, molar ratio of ethanol to DMC 5: 1, 1.0 wt.% of catalyst, the conversion of DMC was 86.4%, the selectivity to diethyl carbonate (DEC) was 61.2%. This heterogeneous catalyst could be used 5 times without loss of its activity.