The invention relates to a method for preparing monomethyl succinate. The monomethyl succinate is prepared by using maleic anhydride and methyl alcohol as raw materials. The method comprises the steps of: 1, dehydrating and removing impurities: adding the methyl alcohol into a dehydrating and impurity-removing device, adding alkali-earth oxides for dehydrating and removing impurities; 2, carryingout solid-liquid separation: ensuring that liquid-phase materials enter the next step; 3, carrying out hemisuccination: adding the maleic anhydride into the liquid phase materials obtained by the step 2; 4, carrying out vacuum distillation: ensuring that the materials subjected to the methyl alcohol removal enter the next step; 5, carrying out electrochemistry reduction: carrying out electrochemistry hydrogenation reduction reaction on a monomethyl cis-butenedioic acid product, water and sulfuric acid; 6, cooling and crystallizing; 7, carrying out solid-liquid separation: ensuring that solid phase materials enter the next step; and 8, carrying out recrystallization separation to obtain the product of the monomethyl succinate. The invention has simple preparation method, reasonable process, low preparation cost, high product purity, good product quality, high yield and convenient implementation for mass industrialization.