Abstract: Taking two times of floor impact in N2105 working face of a mine in the mining process of intake airway passing through syncline structure zone as study object, we theoretically analyze the failure mechanism of roadway floor, and numerically simulate relationship between horizontal stress concentration factor and the change of floor plastic zone. The results show that the higher the horizontal stress concentration coefficient, the more likely to produce a sliding deformation of floor; floor impact damage is caused by superposition of static and dynamic load; large diameter drilling and pressure relief can effectively release pressure to control the roadway floor impact.