Abstract: In order to avoid the threat of water penetration from the goaf of overlying seam No.6 during mining seam No.10 in Shengli coal mine of Linfen, Shanxi, plate-shells theory and fracture mechanics theory were used to establish the mechanics model of the development height of water-conducting fissure zone and the rupture depth of the floor. The water conducting fissure zone developmental height in districts I-VI of coal seam 10 is 46.77 m, 48.86 m, 56.05 m, 56.14 m, 56.33 m and 55.20 m, and the rupture zone depth of the floor in districts I-IV areas of coal seam 6 is 1.57 m, 1.14 m, 1.85 m and 1.26 m. By structuring criteria for water accumulation risk classification of overlying goaf and to determine the risk of accumulated water in the goaf of coal seam 6 during the mining process of coal seam10, the determination result shows that the water accumulation risk in districts I-IV areas of coal seam 6 is of the type of water inrush for seam 10, and would threaten the mining of coal seam10. The influence of the unminable area of seam 6 on the districts V-VI of seam 10 is of permeability of primary rock, and wouldn't threaten the coal extraction in the districts V-VI of coal seam 10.