Abstract: In order to explore the mechanism of action of overlying residual coal pillar on floor stress, Nanliang Coal Mine was selected as the research background. The theoretical deduction and numerical simulation methods were used to construct the collaborative bearing structure model of hinged key block and overlying residual coal pillar. The mechanical characteristics of coal pillar under concentrated load and uniform load were analyzed, and then the stress distribution law of any position in coal pillar floor strata was studied. The results show that the floor stress is mainly controlled by the vertical stress generated by the overlying residual coal pillar, and the stress decreases with the increase of the depth of the rock layer. Through the stress distribution characteristics of any point in the floor strata under different loads, it is found that the stress distribution of the floor under the coal pillar is closely related to the width of the coal pillar, the load intensity of the coal pillar and the buried depth of the floor strata, and the stress distribution law of the coal pillar load acting on the floor of the rock strata under the goaf state on both sides is clarified. Combined with the stress distribution law and numerical simulation results of the residual coal pillar floor strata, it is found that the vertical stress change curve of the floor strata presents the distribution characteristics of ' U ' shape under the influence of the concentrated stress of the coal pillar. The stress evolution characteristics of the overlying remaining coal pillars are revealed, and the stress distribution law and key influential factors of the floor strata under the coal pillars are clarified. The stress distribution mode of the floor strata under the condition of goaf load on both sides is obtained.