Abstract: In order to solve the problem of gas overlimit in the upper corner of fully mechanized caving face in extra-thick coal seam, physical analog simulation experiment was used to analyze the fracture evolution of typical extra-thick gassy coal seam. At the same time, the two dimensional kernel density estimation method was used to study the distribution law of gas transportation storage area above the stope, the optimum stratum of drilling extraction was analyzed and applied in field engineering. The results show that the total bed-separated quantity of the overlying strata is a two-peak distribution of the high side of open-off cut and low side of working face, among them, the height of irregular caving zone is 9.4 m, the height of regular caving zone is 38.0 m, and the height of fissure zone is 158.0 m; the gas transportation storage presents a dynamic trapezoidal distribution, and when the rock formation develops steadily, an obvious temporary reservoir space is formed in the upper part of the regular caving zone, this can be used as the preferred layer for gas extraction, which is 10 m to 40 m away from the roof of coal seam and 5 m to 40 m away from the return airway. During the test period, the gas concentration in the upper corner decreases obviously.