Abstract: In order to study the influence on lower coal mining caused by the instability and collapse of the upper room-pillar goaf, taking the No.5⁻² coal seam longwall comprehensive mechanized mining conditions under the No.3⁻¹ coal seam room-pillar goaf of a mine as the research background, theoretical analysis, numerical simulation and comparison of measured data are adopted. The room-pillar goaf roof caving impact load and its influence depth in the floor and the damage height of the overburden in the lower coal mining are analyzed respectively, and the influence degree of the upper coal on the lower coal mining is evaluated according to whether the influence range of the roof caving impact load extends to the overburden damage range of the lower coal mining. The research method and criterion can provide useful reference for the impact assessment of downgoing mining under similar conditions.