The invention relates to a method for synthesizing dimethyl carbonate. Activate carbon is used as a catalyst, ethylene carbonate and methanol are used as raw materials, and a reaction is carried out in an autoclave at a certain temperature and under a certain pressure. The method is simple to operate, the product and the catalyst can be conveniently separated, the product has high purity, the catalyst has good recycling and reusing performance, and production cost of dimethyl carbonate is greatly reduced.