Abstract: The 30515 fully mechanized top coal caving face of No.3-5 coal seam in Tashan Coal Mine, Datong, China Coal adopts the fully mechanized top coal caving and one-time full thickness mining method, the mining intensity is high and the coal seam structure is complex, and mining under the coal pillar of the overlying short distance goaf for the first time, it is the first time to separate small coal pillars in the air, the impact of mining damage is obvious. There is no experience for surrounding rock movement law, ground pressure behavior and roof control. Therefore, adopts the methods of theoretical analysis and field measurement for the ground pressure behavior law under the special conditions of the working face, the distribution law and failure depth of the concentrated stress of the overlying coal pillar in the floor are theoretically analyzed and studied, the surrounding rock activity law, coal and rock fracture and related stress field changes in the fully mechanized top coal caving face of extra thick coal seam in Tashan Coal Mine are monitored and analyzed, studies the distribution and variation law of super front abutment pressure in the process of mining, formulates targeted roof control measures and mine pressure prevention measures, it is the prerequisite to ensure the safe and smooth mining of the working face, it is of great significance to meet the needs of safety production in Tashan Coal Mine.