Abstract: By combining theoretical analysis,numerical simulation and field observation,the distribution law of abutment pressure during the change of mining thickness in deep coal seam in 41103 working face of Gaojiabao Coal Mine was studied.The results show that the peak value of advance support stress of the coal body is within 13 m in front of the working face under the condition that the coal seam thins from thick,and the advance distance affected by the mining activities is 58 m;the rate of stress change in the mining thickness change area is accelerated,and the peak value of the pre-abutment pressure increases from 38.7 MPa to 46.2 MPa;the peak value of lateral support stress of working face is 12 m in front of working face,where is within 5 m to 11 m deep in the lane,the stress concentration coefficient reaches 2.4,and support shall be strengthened on the basis of advanced support within the area 12 m ahead of the working face.