Abstract: In order to reveal the dynamic ground pressure mechanism of the coal seam working face under the shallow and close distance coal seam group when passing through the residual coal pillar group in the overlying room and pillar goaf, taking the 233101 working face of Hanjiawan Coal Mine as the engineering background, the key block mechanical analysis, physical similarity simulation and field monitoring methods were used to carry out the research. The results show that the superimposition of the leading abutment pressure of the lower layer and the concentrated stress of the left coal pillar promotes the progressive failure and chain instability of the coal pillar, and then causes the leading fracture of the key layer, reverse rotation and the sliding of the lower key block, forming the instantaneous dynamic load. The stability limit load of key blocks in 3⁻¹ coal seam is 1.72 MPa, and the thickness of the critical bearing layer is 11.7 m, which is less than the actual thickness of 22 m; the key block instability occurs when the coal pillar of the working face is 19 m. The peak resistance of the on-site support is 45.0～45.9 MPa, and the mine pressure is characterized by "high in the middle and low at the end". Hydraulic fracturing caused the roof to break in advance, and no strong ground pressure occurred 6 ~10 m after the coal pillar was pulled out. The research reveals the catastrophe chain of "mining in the lower layer - instability of coal pillar - breaking of key strata - dynamic load behavior", which can provide a certain basis for the prevention and control of dynamic load underground pressure under similar conditions.