The invention relates to a method for increasing selectivity of glycollic acid ester. The technical problem of low selectivity of the glycollic acid ester in the prior art is solved. The method comprises the following steps of: taking oxalate as a raw material, and contacting the raw material with a copper-containing oxide catalyst under the conditions of reaction temperature at 100-210 DEG C, weight hourly space velocity at 0.2-5 per hour, mole ratio of hydrogen to ester at (10-100):1 and reaction pressure at 0.5-6.0MPa, thereby generating a reaction effluent containing the glycollic acid ester, wherein the reaction is started by the copper-containing oxide catalyst under oxide state, and on the basis of weight part of the catalyst, the copper-containing oxide catalyst comprises 10-60 weight parts of copper and copper oxide components. According to the technical scheme, the problem is more efficiently solved. The method is suitable for the industrial production for increasing the yield of glycollic acid ester.