Abstract: Grouting pressure and setting pressure are the main parameters for designing an automatic hole sealing device in coal mine, and they are also the important basis for the design of automatic hole sealing construction. Based on the radial sealing range of the slurry, the paper analyzes the sealing effect under different slurry pressure conditions by means of theoretical calculation and numerical simulation. Combined with the mechanical characteristics of the rubber Mooney-Rivlin model, extrusion seal and other principles, the optimal injection pressure and setting pressure are studied and determined. The results show that the radial sealing range of the slurry at a pressure of 2 to 4 MPa is 2 to 4 m, which can meet the sealing requirements for drilling. When the drilling diameter is 96 to 100 mm, the setting seal pressure of 2.2 to 8.4 MPa can make the device achieve the best setting sealing effect. The results can provide a theoretical basis for the design of the device and provides a theoretical basis for determining the technical parameters of the application of the device.