The invention discloses a making method of a platinum iridium oxide alloy electrode. The method includes the following steps: heating and stirring a platinum salt and sodium nitrate mixed solution to 55-65DEG C, carrying out evaporating crystallization, drying, grinding, calcining to obtain a mixture, washing the mixture by water to remove impurities, carrying out full wet grinding, and dispersing the wet ground mixture in a solvent to obtain a platinum dioxide solution; dispersing an iridium salt in the solvent, adding the platinum dioxide solution, adjusting the pH value to 14 by using sodium hydroxide, and dissolving and dispersing to obtain a coating solution; and coating a titanium plate with the coating solution, drying, calcining at 400-700DEG C, and cooling in air to obtain the platinum iridium oxide alloy electrode. The above platinum iridium oxide titanium anode electrocatalysis material prepared in the invention has the characteristics of fine crystsal grains and honeycomb shape; and the anodic chlorine evolution electrocatalytic activity is high, and the service life is long, so the electrode is suitable for preparing electrolyzed oxidizing water, and the use cost is reduced.