Abstract: According to the coal rock occurrence conditions of longwall fully mechanized working face and caving gangue filling characteristics in 49^# right six pieces of steep seam in Xintie Coal Mine, the paper uses FLAC^3D software to simulate rock stress distribution laws and roof and floor destruction features after gangue self-slip filling in the lower parts of goaf. The results of the study show that vertical stress concentration coefficient at the ends of working face is biggest after mining steep seam, stress concentration phenomenon is very serious, and the vertical stress in the goaf rear near the coal wall 15 m away from the face is maximum. With the increase of distance from goaf rear to face coal wall, shear stress first decreases, and then increases, and finally becomes stable. The shear stress is minimum when the goaf rear is away from the face coal wall 34 ~ 38 m. Roof plastic damage of working face is violent, the plastic damage ways are various, the face floor is less damage, destroy is simple in form, the damage height of roof upper end is small, the damage height of roof lower end is big.