The synthesis of di-methyl-carbonate (DMC) with urea and methanol occurred by two step reactions. In first step, methyl-carbamate (MC) is produced by the reaction between urea and methanol. In second step, DMC is synthesized by the catalytic reaction between MC and methanol over the catalyst. In this study, ZnO was used as the catalyst for the synthesis of DMC and the reaction behavior for the synthesis of DMC over ZnO catalysts, which have a different surface area, was investigated. The surface area of ZnO was controlled with the change of calcination temperature and that calcined at with 400℃ was 27㎡ /g. Meanwhile, the yield of products was investigated with the reactionconditions, such as the temperature, the pressure, the time, the amount of catalyst and the agitation speed. The yield of DMC was changed with changing reaction conditions. It was also concluded that the production of N-methyl-methyl-carbamate (N-MMC), which is the by-product produced by the reaction between MC and DMC, taken affected in the yield of DMC. The maximum yield of DMC was obtained to approximately 23.9% in the test under the suitable reaction conditions, which was performed with 1 gram of catalyst at 175℃, 25 bar and 600 rpm for 10 h. The yield of DMC increased with the increase of catalyst’s surface area, while the changing surface area of catalyst was exhibited the little effect for the production of N-MMC.