Abstract: The inner accessory ingredients, at first, are defined as the accessory ingredients contained within the natural sulfur-fixing agent, and the desulfuration effect of the sulfur-fixing agents with the inner accessory ingredients is studied by contrast with the agents to which the accessory ingredients are added. The results indicate that the sulfur-fixing agents with the inner accessory ingredients have higher sulfur-fixing rate than the contrast sulfur-fixing agents because the effect of supporting fixation sulfur can be give full play to, and, especially, the sulfur-fixing ratio of the sulfur-fixing agents with the inner accessory ingredients can still amount to 25.7%~35.5% at 1200℃, is 5~6 times as high as the contrast sulfur-fixing agents.