Abstract: In order to study the fracture evolution laws of surrounding rock under different strata rock structures in short-distance coal seam group, based on the background of the coal seam group in Shendong Coal Mine, the interlayer structure was classified by the key strata theory, and four UDEC numerical models were established according to the distance between different layers and the number of inferior key strata. The conclusions were as follows: when there was only one inferior key strata between the two coal seams, the increase of the distance between these two coal seams would have little effect on the fracture evolution of the overburden rock mass; the location and number of inferior key strata would affect the dynamic development and distribution of overburden fissures, while it would not affect the height of fracture distribution; the two inferior key strata with same properties and thickness would decrease the range of fracture distribution.