The invention relates to the field of ethanol preparation, and discloses a method for preparing ethanol by hydrogenation of acetic acid. The method comprises the following steps: separately preheatingan acetic acid raw material and hydrogen, carrying out mixing and gasifying, heating the gasified material flow, then carrying out a catalytic hydrogenation reaction, cooling the product of the hydrogenation reaction, and carrying out first gas-liquid separation to obtain a liquid phase mainly containing ethanol and a gas phase mainly containing hydrogen; carrying out an esterification reaction on the liquid phase to remove residual acetic acid, then carrying out cooling to obtain an ethanol crude product, carrying out downstream purification treatment on the ethanol crude product to obtain an ethanol product, and separating out ethyl acetate; and then, separately preheating the ethyl acetate and a part of the gas phase obtained by the first gas-liquid separation, then carrying out mixingand gasifying, heating the gasified mixed material flow, then carrying out an ester hydrogenation reaction, and carrying out second gas-liquid separation on the product of the ester hydrogenation reaction to obtain an ethanol crude product and a gas phase mainly containing hydrogen. The method can eliminate residual acetic acid as early as possible, reduce corrosion of equipment, and can recycleethyl acetate to improve the conversion rate of acetic acid.