The invention discloses a gold concentrate oxidizing slag gold leaching process, which comprises the following steps: firstly, leaching the gold concentrate oxidizing slag for the first time by using a leachate and activated carbon to obtain gold-loaded carbon and mixed ore pulp; then supplementing activated carbon and the leachate into the mixed ore pulp, adjusting the pH value, and then carrying out secondary leaching to obtain a leaching solution, gold-loaded carbon and tailings; finally, recycling the leaching solution for continuous leaching; wherein the leachate is ammonium thiocyanate. The process is used for the high-arsenic sulfur gold concentrate with the arsenic content exceeding 15%, the leaching rate is 95% or above, other energy consumption is avoided, the leaching condition is simple, and the industrial realizability is high; the leaching solution is recycled and re-leached, so that the dosage of chemicals and water is saved, and meanwhile, the two-stage leaching ensures that the gold leaching rate is high and the index is stable; ammonium thiocyanate is adopted as the leachate, the leachate is easy to obtain, low in cost, safe and non-toxic, the gold leaching speed is high, the leaching period is short, leaching waste liquid and waste residues are easy to treat, and the cost is low.