The invention belongs to the technical field of solid waste treatment, and discloses an innocent treatment method of toxic solid waste containing hexavalent chromium. The innocent treatment method comprises the steps that sodium bicarbonate powder is added to the pretreated toxic solid waste containing Cr and acts as an activating agent for grinding, and CO2 is supplied in the grinding processfor protection so as to prevent organic matter impurities remained in the toxic solid waste from exploding; then ground waste is screened, undersized powder is placed in a reactor and is heated to 180-300 DEG C, and a reaction is made with the temperature being kept for 1.5-3 h; and water is injected to the reactor for cooling, then sodium carbonate is added and acts as a mineralizer, mixing is carried out uniformly, a reaction is made with the temperature being kept at 70-200 DEG C for 3-10 h, cooling of the room temperature is carried out, and centrifugal separation is carried out, thus solid waste after innocent treatment is obtained. By employing the synergistic effect of sodium carbonate and sodium bicarbonate, the treatment cost of chromium slag can be lowered substantially, and thetreatment efficiency of waste slag is improved substantially.