Abstract: Based on analysising coal seam floor dynamic failure mechanism, this paper established strata buckling fracture mechanics model. Research showed th at main influence factors on the stability of roadway floor strata were horizontal stress, and has proposed the calculating method for floor horizontal stress. According to theoretical calculation obtained the maximum delayering thickness and damage range for the floor buckling under the action of the maximum horizontal stress. Researc h results showed that strengthened the floor support strength could effectively control floor heave and dynamic failure, shotcrete and 36U profile steel and fender suppo rt way could reduce roadway deformation about 50% and effectively controlled floor heave.