Spontaneous combustion of sulfide ores during mining can lead to severe fires. To explore the transformation of state in the whole process of spontaneous combustion of sulfide ores, the simulation experiment of the whole unsteady process of spontaneous combustion of sulfide ore heap was carried out, and the most appropriate wavelet function was selected, combined with catastrophe detection and other methods for data mining and processing. The results indicate spatial differences in the response of the ore heap to environmental temperature changes during the whole unsteady process of spontaneous combustion of the sulfide ore heap. The reaction in the area near the surface of the heap is more prominent and faster, and the response in the area near the center of the heap is longer in duration. Moreover, there must be at least one catastrophe point in this process, and the catastrophe temperature must be between 108.2 °C and 113.9 °C. Finally, the whole unsteady process of the spontaneous combustion of the sulfide ore heap can be divided into four regions. Among them, region (II) is in a stage of obvious self-heating/near spontaneous combustion, and it is the catastrophe stage.