Abstract: According to the poor applicability of the current empirical formula of floor failure depth in the regulations in Chenghe mining area, this paper, combined with the engineering geological and hydrogeological conditions of the roof and floor of No.5 coal seam in Chenghe mining area, makes numerical calculation and analysis of floor disturbance failure depth under the conditions of two-factor and multifactor respectively. Based on the results of numerical simulation, the fitting formulas for the floor failure depth in Chenghe mining area are obtained. And the results are compared with the measured values of floor failure depth of the 26 coal seams in North China type coalfield. The results show that the nonlinear fitting regression formula proposed in this paper has stronger prediction ability, higher prediction accuracy and smaller error range, which can meet the field needs of Chenghe mining area, and provide evaluation basis and scientific guidance for mining under pressure.