Abstract: For the serious deformation, dynamic impact and other problems in the advancing support section of coal roadway under the condition of retaining pillar of 38 m to 43 m in Carboniferous No.3-5 extremely thick coal seam of Datong Mining Area with hard roof, by combining theoretical analysis, field measurement and numerical simulation, we studied the mechanism of the occurrence of strong pressure in advance supporting section of coal roadway, the results show that the superposition of high support pressure in the two goaf areas and the creep effect of coal rock mass are the fundamental reasons for the occurrence of strong pressure in the leading supporting section of the coal roadway; the fracture of overlying K₃ sub-critical layer of working surface will lead to the formation of high supporting pressure zone around the goaf and the influence range of support pressure is 110 m to 150 m; we proposed the concept of surface cycle ratio, and the peak strength and peak position of support pressure increase linearly with the increase of surface cycle ratio, while the influence range of support pressure is basically unchanged. We proposed and implemented the technology of roadway protection for narrow pillar with hard roof in ultra-thick coal seam. The field test of 5204 lane in 8204 working face of Tashan Coal Mine achieved good results and ensured the normal production of working face.