The invention provides a one-step technology for synthesis of ethyl methyl carbonate and co-production of 1,2-propanediol and relates to a technology for synthesizing ethyl methyl carbonate. Accordingto the technology, ethyl methyl carbonate, diethyl carbonate and 1,2-propanediol are directly synthesized in one step by catalysis of a multifunctional composite alkaline material catalyst. Azeotropic separation is performed synchronously while reactive distillation is performed, a solvent is not needed for extraction and separation of a product, and accordingly, the conventional technological process of synthesis of ethyl methyl carbonate is greatly simplified; meanwhile, multiple components are separated at a time, and the separation purity is high. The maximum selectivity of ethyl methyl carbonate in a crude product obtained by the reaction can reach 70%, and dimethyl carbonate and diethyl carbonate as byproducts can be taken as products to be separated directly and can also be recycled to be reacted continuously for generation of ethyl methyl carbonate, and the byproduct 1,2-propanediol can be taken as a bulk raw material to be separated by simple distillation. The whole reactionprocess is clean, efficient and pollution-free, and no waste is generated.