Abstract: The development height of water flowing fractured zone in overlying strata of coal seam in the same mining area is different. If the multiple of mining height is used to determine the development height of water flowing fractured zone, there is a large deviation from the actual development height. In order to study the maximum development height of water flowing fractured zone in overburden strata, 2-2 coal seam in Xiaobaodang mining area is taken as the research object. Through theoretical analysis, similar material simulation experiment, case verification and other methods, on the basis of applying limit curvature to predict the development height of water flowing fractured zone, the distance between the upper strata of water flowing fractured zone and coal seam, subsidence coefficient, mining height and the maximum curvature deformation value of the upper strata of water flowing fractured zone are organically combined by means of probability integral method. The relationship between the development height of the upward fractures in the overlying strata with the maximum curvature deformation value of the upper strata of the water-conducting fracture zone as the key parameter and the relationship between the development depth of the downward fractures with the maximum horizontal tensile deformation value as the key parameter are given. On this basis, a theoretical prediction method for the development height of water flowing fractured zone based on probability integral method is given. The maximum development height of water flowing fractured zone in overlying strata of 2-2 coal seam mining in Xiaobaodang mining area is predicted by using this prediction method. The maximum development height is 160.1m, which is basically consistent with the field measurement of 152.01m ~ 175.57m. The research results can provide theoretical basis for realizing water-preserved mining under similar working conditions.