Abstract: For the special reality of much residual coal, serious air leakage and the dangerous possibility of coal seam spontaneous combustion of the crossheading roof in side-impending goaf of half isolated island fully mechanized caving face, the reasons of coal seam spontaneous combustion of crossheading roof were analyzed. Then according to the practical situation of 3-105 working face, the pre-control technology of the coal seam spontaneous combustion of the crossheading roof in side-impending goaf including the forecast technology of spontaneous combustion, plugging-wind technology and pressure injection of fire prevention material was put forward, which effectively prevented the accidents of coal spontaneous combustion in side-impending goaf of 3-105 half isolated island fully mechanized caving face.