The invention discloses a gold nano membrane electrode preparation method and a gold refining method. The gold nano membrane electrode preparation method comprises the following steps: adding electrolyte into an electrolyzer, wherein the electrolyte is composed of AuCl3 solution and concentrated hydrochloric acid, and the amount of the concentrated hydrochloric acid is controlled to keep pH value of the electrolyte less than 1; putting the electrolyzer in ultrasonic wave with frequency of 20-30kHz; dipping a pure gold anode and a titanium sheet cathode in the electrolyte; and controlling the decomposition voltage to keep asymmetric current density of the electrolyte is within 600-1000A/m2 to enable gold to be separated out at the cathode to develop gold nano membrane to obtain gold nano membrane electrode. The gold nano membrane electrode can be used for asymmetric current high purity gold refining production; the characteristic of electro-catalysis of the gold nano membrane is used for reducing oxidation-reduction potential and improving current density, so as to speed up gold separation at the cathode, reduce the raw material amount of gold, decrease consumption, improve gold purity and the like, thereby realizing better economic and social benefits.