NOVELTY - A platinum-containing compound and a chromium-containing compound are dissolved in a solvent. Sodium acetate and sodium hydroxide are added. An alkaline solution of gas is added, and reaction is carried out in carbon monoxide atmosphere to obtain metal carbonyl cluster compound solution. A carbon carrier is added to the solution and heat-stirred. The solvent is removed, and the obtained intermediate is heated, cooled, heated in pure hydrogen atmosphere, cooled, washed, and dried to obtain a carbon-loaded nano platinum-chromium intermetallic compound.    USE - Preparation of carbon-loaded nano platinum-chromium intermetallic compound for cathode catalyst of proton-exchange membrane fuel cells (claimed).    ADVANTAGE - The method enables preparation of carbon-loaded nano platinum-chromium intermetallic compound in which the intermetallic compound is distributed uniformly. The obtained compound has excellent electrocatalytic oxygen reduction property and stability.    DETAILED DESCRIPTION - A platinum-containing compound and a chromium-containing compound are dissolved in a solvent and stirred for complete dissolution. The molar ratio of platinum and chromium is 1:0.25-3. Sodium acetate and sodium hydroxide are added such that the molar ratio of sodium acetate with respect to platinum element is 3-10 times and the molar ratio of sodium hydroxide with respect to platinum element is 0-5 times. An alkaline solution of gas is added, and reaction is carried out in carbon monoxide atmosphere at 40-80 degrees C for 2-36 hours, to obtain metal carbonyl cluster compound solution. A carbon carrier is added to the solution in a mass ratio of 0.3-5 times with respect to platinum element, and heat-stirred at 50-80 degrees C for 2-12 hours. The solvent is removed, and the obtained intermediate is heated at 300-500 degrees C for 3-10 hours under gas protection, and cooled. The product is heated at 650-800 degrees C for 3-10 hours in pure hydrogen atmosphere, cooled, washed with water, and dried to obtain a carbon-loaded nano platinum-chromium intermetallic compound.