The invention relates to a use method of a sulfide as a gold extraction auxiliary agent of sulfating roasting slag. The use method comprises the following steps of: adding the roasting slag, the sulfide serving as the gold extraction auxiliary agent and water into a reaction kettle, wherein the mass ratio of the sulfide serving as the gold extraction auxiliary agent to the roasting slag is 1:(0.5-80); uniformly stirring; heating to the temperature of between 40 and 100 DEG C; adding an aqueous solution of sulfuric acid for acid dissolution; reacting for 10 minutes to 6 hours; filtering to obtain filtrate and filter residue while a reaction product is hot; and finally extracting noble metal from the filter residue by using the conventional method. By adopting the use method, the leaching rate of iron in a roasting slag acid leaching process is increased, the effect of a subsequent gold extraction process is favorably promoted, the requirements for environmental protection and industrial production are met, and economic benefit is also improved; and the sulfide serving as the gold extraction auxiliary agent of the sulfating roasting slag is low in cost and readily available and has good industrial application prospect.