The invention provides a method for one-step synthesis of ethyl methyl carbonate and combined production of 1,2-propylene glycol, and relates to the method for synthesizing the ethyl methyl carbonate.The invention discloses a highly-efficient alkaline catalyst with a composite pore structure for one-step synthesis of the ethyl methyl carbonate from propylene carbonate, methanol and ethanol. According to the invention, a crude product obtained by a reaction comprises dimethyl carbonate, the ethyl methyl carbonate, diethyl carbonate and 1,2-propylene glycol, wherein the highest selectivity of the ethyl methyl carbonate can reach 78%; the by-products of the dimethyl carbonate and the diethyl carbonate can be directly separated as products or recycled to continue the reaction for generation of the ethyl methyl carbonate; and the by-product of the 1,2-propylene glycol can be separated as a bulk raw material through simple distillation. The method provided by the invention has the advantages of cleanness, high efficiency, no pollution and no generation of wastes in the whole process of the reaction; and when the mol ratio of the propylene carbonate to the methanol to the ethanol is 1: 3: 2, the reaction has a pressure of 5 MPa, a temperature of 100 DEG C and a space velocity of 5 h-1, and the catalyst is not inactivated after used for 5000 h and has good stability.