The catalytic synthesis of dimethyl carbonate from methyl carbamate and methanol was investigated in a batch reactor. All of the homogeneous Bronsted acid catalysts show favorable catalytic activity. As homogeneous Bronsted acid catalyst is difficult to separate after reaction, it is converted to heterogeneous catalyst by grafting sulfonic acid groups to MCM-41 with three different methods. Their catalytic activity investigation indicated that sulfonic acid groups grafted by sulfonating with chlorosulfonic acid directly showed activity near to that of homogeneous sulfuric acid catalyst. It was further selected as a model catalyst to investigate the effect of acid amount on its catalytic activity. The results indicated that its activity was positively correlated with its acid amount.