Abstract: The horizontal coal seam mining in Huojitu Mine shaft of Daliuta Mine belongs to close distance coal seam group mining, the interval between layers of coal is generally 0 to 28 m, and there is the problem of over concentration of coal pillar when the coal seam is mined, which often results in dynamic load and top cutting. In order to explore the mechanism of top cutting of over-concentrated coal pillar in the special section of 22# coal, a mechanical model of top cutting mechanism was established by taking the 22311 working face as the prototype and analyzing the law of strata behavior during the final mining period. The step spacing of 22311 working face is calculated to be 8 m, and the mechanism of top cutting, floor heave and rib spalling in 2-4 connecting roadway of withdrawal channel is analyzed. Meanwhile, countermeasures and control measures are formulated.