Increasing the permeability of coal reservoirs is a key technology to improve the recovery rate of coalbed methane, and in-situ thermal injection mining is an effective method to enhance coalbed methane production. In order to explore the change rule of coal reservoir permeability under the coupling of heat, fluid, and solid, pyrolysis seepage experiments of anthracite with different burial depths and temperatures were conducted, and theoretical analysis and research were conductedon the experimental results. The results showed that: (1) Under three-dimensional effective stress, the permeability of pyrolysis anthracite varies with temperature and pore pressure in a "V" shape, with a significant rebound phenomenon, which decreases with the increase of burial depth. When the pore pressure is less than the

critical pore pressure and the temperature is less than 70℃, the permeability of the coal body mainly depends on the slippage effect. When the pore pressure is greater than the critical pore pressure and the temperature is greater than 70℃, the permeability mainly depends on thermal expansion and the opening degree of pore pressure on the fracture , and the impact of thermal stimulation on the permeability is much greater than the pore pressure. (2) The critical pore pressure is between 1~1.5 MPa, and the influence of slippage effect on permeability gradually decreases with the increase of temperature, and the gradient of influence reduction increases with the increase of burial depth. (3) The fracture opening coefficient increases with the increase of temperature and burial depth, but the higher the temperature, the smaller the change in the sensitivity of permeability to pore pressure under different

burial depths. These research results further enrich the theory of in-situ thermal injection mining of coalbed methane, and provide valuable data reference for enhanced permeability of coalbed methane.