Abstract: In this paper, based on the limit equilibrium theory and the ultimate bearing capacity of coal, the expression of the influence range of the advance support stress of the coal face is derived. As a starting point, the evolution of the overbearing stress evolution of the coal wall before and after the breakage of the key strata in the overlying strata of the working face mining stage is analyzed and calculated respectively. Theoretical calculation analysis results and the actual engineering verification indicate that the peak value and the influence range of the coal wall in front of the coal wall are smaller than that of the key layer after the breakage of key strata in the overburden strata.