Abstract: In order to study the influential law of different working face widths on the surface subsidence reduction of the overburden isolation grouting technology application in Dashe Mine, taking the 921102 trapezoidal working face of Dashe Mine as the research object, by using the methods of theoretical calculation and 3DEC numerical simulation, six design schemes of overburden grouting under different working face widths(60 m, 80 m, 100 m, 120 m, 140 m, 160 m)are established.The supporting effect of grouting filling materials on the key strata of overburden and the influential laws of different working face widths on surface subsidence reduction and surface inclination of the working face are analyzed.The results show that with the increase of working face width, the maximum surface subsidence also increases at the same time, and the increase amplitude of subsidence gradually decreases.The fitting curve of working face width and maximum subsidence is y=-226.952 4-4.957 1x,showing a linear relationship.With the increase of working face width, the surface inclined deformation also increases at the same time.The fitting curve of working face width and surface inclined deformation is y=0.277 1+0.021 6x.Within a certain range, the working face width and surface inclined deformation value show a linear relationship.According to the analysis of measured results, the subsidence rate is divided into three stages: Initial period(<0.6 mm/d),active period(>0.6 mm/d),and attenuation period(<1.67 mm/d).The field industrial results are basically consistent with the numerical simulation results.When the working face width is less than 160 m, the surface inclined deformation can be controlled within 3.6 mm/m.