A method for preparing ethylene glycol by hydrolysing ethylene glycol monomethyl ether, which comprises: passing a fresh raw material containing ethylene glycol monomethyl ether and water through a reaction zone loaded with a solid acid catalyst to react under the following conditions; separating the reacted mixture via a separation system to obtain a target product of ethylene glycol, by-products containing methanol, dimethyl ether and ethylene glycol-based derivatives, and an unreacted raw material containing ethylene glycol monomethyl ether and water; passing the target product of ethylene glycol into a product collection system; and passing methyl alcohol and dimethyl ether in the by-products into a by-product collection system; and after being mixed with the fresh raw materials containing ethylene glycol monomethyl ether and water, the ethylene glycol-based derivatives in the by-products and the unreacted raw material containing ethylene glycol monomethyl ether and water being recycled into the reaction zone, to realize the preparation of ethylene glycol by hydrolysing ethylene glycol monomethyl ether; wherein, the solid acid catalyst is one or two catalysts selected from the group consisting of acidic molecular sieve catalysts and acidic resin catalysts; the reaction zone is constituted by one or more reactors which are connected in series and/or in parallel; the ethylene glycol-based derivatives is one or more derivatives selected from the group consisting of ethylene glycol dimethyl ether, 1,4-dioxane, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, diethylene glycol and triethylene glycol; the reaction conditions are listed as follows: the reaction temperature is in a range from 100°C to 250°C, and the reaction pressure are in a range from 0.5MPa to 10MPa, and the weight hourly space velocity of ethylene glycol monomethyl ether in the fresh raw material is in a range from 0.1h -1 to 10h -1. passing a fresh raw material containing ethylene glycol monomethyl ether and water through a reaction zone loaded with a solid acid catalyst to react under the following conditions; separating the reacted mixture via a separation system to obtain a target product of ethylene glycol, by-products containing methanol, dimethyl ether and ethylene glycol-based derivatives, and an unreacted raw material containing ethylene glycol monomethyl ether and water; passing the target product of ethylene glycol into a product collection system; and passing methyl alcohol and dimethyl ether in the by-products into a by-product collection system; and after being mixed with the fresh raw materials containing ethylene glycol monomethyl ether and water, the ethylene glycol-based derivatives in the by-products and the unreacted raw material containing ethylene glycol monomethyl ether and water being recycled into the reaction zone, to realize the preparation of ethylene glycol by hydrolysing ethylene glycol monomethyl ether; wherein, the solid acid catalyst is one or two catalysts selected from the group consisting of acidic molecular sieve catalysts and acidic resin catalysts; the reaction zone is constituted by one or more reactors which are connected in series and/or in parallel; the ethylene glycol-based derivatives is one or more derivatives selected from the group consisting of ethylene glycol dimethyl ether, 1,4-dioxane, diethylene glycol monomethyl ether, diethylene glycol dimethyl ether, triethylene glycol monomethyl ether, triethylene glycol dimethyl ether, diethylene glycol and triethylene glycol; the reaction conditions are listed as follows: the reaction temperature is in a range from 100°C to 250°C, and the reaction pressure are in a range from 0.5MPa to 10MPa, and the weight hourly space velocity of ethylene glycol monomethyl ether in the fresh raw material is in a range from 0.1h -1 to 10h -1.