Abstract: Based on the present situation that protective layer mining is the most effective measure to control low permeability and high gas outburst coal seam,aiming at the mining of protective layer in thin coal seam and extremely thin coal seam,the mining method of semi-coal rock protective layer working face with cutting soft floor to increase mining height is proposed.Taking the 3203 protective seam working face of Zhongxing Coal Mine as the engineering background,the maximum failure depth of the floor rock mass after the mining of the 3203 protective seam working face was calculated by the slip line field theory,and the pressure relief and permeability enhancement effect of the mining of the upper protective seam of semi-coal rock was discussed by using the numerical simulation method.The results show that after the mining of 3203 protective seam working face,the maximum failure depth h_max of floor rock mass reached 20.74 m,and the horizontal distance between the maximum failure depth of floor and the coal wall of working face was 13.99 m.The pressure relief rate of 3203 protected layer reached 0.58,and the expansion deformation rate of 3203 working face was greater than 6‰.The residual gas content was 4.57 m³/t,desorbable gas W_j=0.68 m³/t,the permeability coefficient of coal seam increased from 0.043 7 m²/(MPa²·d) to 1.08 m²/(MPa²·d),the porosity increased from 3.5% to 4.05%,and the residual gas pressure was 0.31 MPa.The purpose of efficient,safe and economic production of outburst coal seam in high gas mine was effectively realized.