The present invention relates to a methyl propionate preparation method, which comprises: mixing methanol and a ruthenium-supported metal oxide catalyst, placing the obtained mixture in a pressure container, filling with ethylene and carbon monoxide, sealing, and stirring, wherein the reaction temperature is more than or equal to 130 DEG C, the reaction time is more than or equal to 2 h, and the ruthenium-supported metal oxide catalyst is one or a plurality of material selected from Ru/TiO2, Ru/Nb2O5, Ru/CeO2 and Ru/Al2O3. According to the present invention, with the method, the catalyst is easily separated from the reaction system after the reaction, and can be used repeatedly, and the yield of propyl formate is up to 90%.