Abstract: To assess the effect of pyrrhotite on pyrite dust explosion, a 20 L sphere vessel and a test device for the minimum ignition temperature of dust clouds were employed to investigate the influences of pyrrhotite on the parameters of the maximum explosion pressure (P_max), the maximum explosion pressure rise rate (dP/dt)_max, the minimum explosive concentration (M_EC), and the minimum ignition temperature of primary pyrite (hereinafter referred to as raw ore), pyrite pure minerals collected by the mine. The mechanism of pyrrhotite affecting the chemical reaction of pyrrhotite dust explosion was analyzed based on the results of composition and surface structure of explosive products. The results indicate that pyrrhotite can increase the probability of chemical reaction between oxygen and pyrite particles in the raw ore, and decrease the M_ITC and M_EC of the pyrite dust cloud, thereby increasing the P_max and explosion temperature of the pyrite dust cloud. Additionally, the explosion products of pyrite and magenetite dust are controlled by the explosion temperature, and the final products are Fe₃O₄ and SO₂. The explosion reaction process is consistent with the shrinking core-diffusion limited volatile explosion model.