The invention discloses a method for preparing a copper bismuth catalyst used for synthesis of 1,4-butynediol. The method comprises the following steps: employing a co-current flow method, dropping an acidic solution and a precipitating agent solution in a reaction vessel, introducing gas CO2 from bottom of the reaction vessel; when the residual acidic solution accounts for 2/3-3/4 of total amount of the acidic solution, stopping a reaction, aging the material; after the aging is completed, transferring the 1/3-1/4 of the reaction products in the reaction vessel into a second reaction vessel, continuously dropping the materials in the second reaction vessel, keeping the liquid surface height of the second reaction vessel as the height before dropping, transferring the superfluous reaction products to the first reaction vessel, introducing gas CO2 into two reaction vessels; after the reaction is completed, mixing the solutions in two reaction vessels, aging, and performing spray drying to obtain the copper bismuth catalyst. The catalyst has the advantages of good wear resistance, uniform and moderate particle size of the catalyst, and high activity stability.