The mining of the lower group of coal directly affects the upper coal and its top and bottom, and the thickness of the interlayer rock and its fall characteristics are the key to whether it can be used for ascending mining. Based on the interlayer rock between the No.4 coal seam and the 42 mining coal seam of Lvliang mine, according to the variation of interlayer rock thickness, theoretical analysis, numerical simulation and field measurement were used to study the influence of different thickness interlayers and their slump characteristics on the ascending mining. Research indicates that: when the interlayer rock thickness ranges from 18.2 to 28.2 m, the 42 coal mining zone is located in the fracture zone of the No.4 coal seam, and the top and bottom plates are relatively complete for upward mining; at the same time, a suspended structure appears above the boundary of the No.4 coal seam goaf, and measures such as bottom plate filling and inclined working face can be avoided during the ascending mining to avoid the occurrence of mine pressure disasters. When the thickness of the interlayer rock is 10.2 m, the coal seam in the 42 mining area is located at the junction of the regular falling zone and the fracture zone of the No.4 coal seam; the coal seam and its top and bottom of the 42 mining area are seriously damaged, and mining is not recommended. When the interlayer rock thickness ranges from 10.2 m to 18.2 m, the 42 coal seam is in the fracture zone of No.4 coal seam, but the fracture is relatively developed; it is necessary to adopt a series of safety technical measures or extend the interval before mining. This study can provide a theoretical basis and engineering reference for the feasibility analysis of upward mining under similar conditions.