Abstract: In order to avoid the misjudgment of the stability of the mine dump due to the deviation of the calculation results of the stability of the mine dump，based on the research results of the stability of multiple primary and secondary dumps，the method of combining specific calculation with on-site practice is used to clarify the accurate acquisition of the physical and mechanical parameters of the basement rock and soil layers and dump materials in the dump. The idea of modeling the upper-middle-lower three-zone layered structure of the single step of the dump and incorporating the saturated layer into the calculation within the surface infiltration depth is proposed. The example calculation shows that the stability coefficient calculated by the single-step generalized three-zone layered structure model is reduced by about 2%. The stability coefficient calculated by setting the 10 m depth range of the surface layer of the dump as the transient saturated layer and assigning the physical and mechanical indexes of the saturated material is reduced by about 6%. When both are considered，the stability coefficient is reduced by about 8%. It reflects the real situation of the stability coefficient of the dump，indicating that the fine calculation of the stability of the mine dump is achievable.

Key words: mine dump, three-band layered structure, infiltrative depth, transient saturation layer, fine calculation