Abstract: Spontaneous combustion is easy to occur in the composite coal seam mining under the condition of positive pressure ventilation, which seriously threatens the mine safety production. In order to solve the problem of spontaneous combustion in fully mechanized working face of composite coal seam, which is easy to spontaneous combustion in positive pressure ventilation mine. Taking the specific practice of fire prevention and control in goaf of 12_down203 fully mechanized working face in Daliuta Coal Mine composite area as an example, based on the regional location and mining conditions of the working face, measures such as reinforcement of the canopy area, intubation water injection, combination of underground high-level drilling and ground borehole grouting, blocking air leakage channels up and down the well, and strengthening gas detection in abnormal areas are taken to reduce the CO volume fraction in the fire area to the normal level, and there is no natural combustion sign gas such as C₂H₂, which effectively eliminates the underground combustion point and provides technical guarantee for the mine safe production.