The invention discloses a method for one-step synthesis of methyl ethyl carbonate by using ethylene carbonate, methanol and ethanol, and relates to the method for synthesizing the methyl ethyl carbonate. According to the method provided by the invention, a high-efficiency basic catalyst with a composite pore structure is used for the one-step synthesis of the methyl ethyl carbonate by using the ethylene carbonate, the methanol and the ethanol. The crude product obtained by a reaction contains dimethyl carbonate, methyl ethyl carbonate, diethyl carbonate and ethylene glycol, wherein the selectivity of the methyl ethyl carbonate can be up to 77%. The by-products, dimethyl carbonate and diethyl carbonate, can be directly separated out as products, and can be recycled for continued reaction for generating the methyl ethyl carbonate; and the by-product ethylene glycol can be separated out through simple distillation as a bulk raw material. The whole reaction process is clean, efficient andfree of pollution, and no waste is generated. When the molar ratio of the ethylene carbonate to the methanol to the ethanol is 1:3:2, the reaction pressure is 5 MPa, the reaction temperature is 100 DEG C, and the space velocity is 5 h<-1>, the catalyst is not deactivated and has good stability after being used for 5000 hours.