Abstract: Based on Hoek-Brown experience criterion correction formula, it estimated the values of rock disturbance coefficient D and geological strength index GSI in different depth of floor strata, judged floor damage degree. Combined with the field observation data of 1028 working face in Suntuan Coal Mine, it carried out example analysis for floor vertical stress component from 5 m coal seam, and it obtained floor stress distribution by theoretical calculations. In order to further verify the feasibility of the example analysis, it made numerical simulation with FLAC^3D software for 1028 working face of Suntuan Coal Mine, both of floor stress distribution results coincided under the same conditions. It simulated the influence of different excavation steps for the floor stress and displacement, and further studied floor migration failure mechanism and law of water inrush of mining on confined aquifer.