Abstract: In order to study the occurrence of coal mine disasters such as roof collapse, impact ground pressure, coal wall flake gang, and gas explosion after the formation of high stress zone by the influence of overlying coal pillar on the working face of lower coal seam during the downward mining of close coal seam group.In this paper, the authors use FLAC^3D software to numerically simulate and analyze the dynamic change law of roof stress distribution before and during mining of the lower coal seam with the overlying coal pillar of 1 m, 2 m, 3 m and 5 m thickness respectively.The results show that before the lower coal seam is mined, the overlying coal pillar will make the lower coal seam in the stress concentration state; when the thickness of the coal pillar increases, the peak value of the supporting stress field, stress concentration coefficient and stress concentration area of the roof of the lower coal seam gradually decreases, and the peak value of the supporting stress field is always near the center line of the coal pillar.With the increase of the working face advancement distance, the stress concentration area in front of the mining area gradually decreases, the peak of the supporting stress field and concentration coefficient first increases and then decreases; in the process of working face advancement, the smaller the thickness of the coal column, the larger the peak of the supporting stress, concentration coefficient and concentration range of the roof plate in front of the working face, the smaller the distance between the stress concentration area and the working face, the more attention should be paid to prevent the occurrence of mine disaster accidents such as roof rise and roof crushing.