Abstract: Aiming at complex processes and difficulties of hole sealing of hydraulic fracturing in coal mines, theoretical study for the pressure bearing characteristics of borehole capsule packer was carried out. Two conditions of effective hole sealing with capsule packer were proposed, the first one was that the friction force of the borehole surface to the packer should be bigger than the thrust force of the high pressure water in borehole to the packer, the other one was that the effective pressure that the packer to the borehole surface should be bigger than the maximum injection water pressure of hydraulic fracturing. Theoretical analysis indicated that if the length of the packer was longer than the critical length, the higher the pressure inside the packer was, the longer the packer segment was, the smaller the borehole diameter was, and the greater the water injection pressure bearing would be. Otherwise, the maximum pressure bearing ability of hole sealing was dominated by the water pressure inside the packer. The hydraulic fracturing hole sealing parameters of Yuwu Coal Mine S2107 high level suction roadway was determined based on the conclusion, the hole sealing effect was good, which provided guidance for the design of borehole packer and its application.