Aiming at the characteristics of huge thickness, low gas content and low seepage of coal reservoir in Jirgalangtu Depression of Erlian Basin, a geological model was established, and the combined method of rock-electricity-well-seismic was used to carry out the fine layer calibration, and the criteria for the division of dessert area of huge thick coal seams were determined; the results show that: the stratum is divided into 6 coal groups from top to bottom, and the upper part of the groups shows the sedimentary characteristics of mudstone and interbedded coal seam. The upper part of the coal group is characterised by mudstone and coal seam interbedding, and the middle and lower part of the group is characterised by the development of 60–100 m thick coal seam. The coal seams change a lot, generally showing thin in the west and thick in the east, the middle is thick and continuous, the two sections become thin and bifurcated, and the north–south direction is thick and continuous in the middle and thin and bifurcated on both sides, and the tectonically gentle area with the thickness of a single layer greater than 40 m and the abundance of resources greater than 1.5 × 108 m3/km2 should be preferred as a Class I dessert area; in order to guarantee the high and prolonged seam heights, and to increase the controlled reserves in single wells, we screened the high-quality layer segments and focused on shot-hole fracturing to form the In order to ensure the fracture height and prolong the fracture length of single well, the fracture modification technology for thick reservoirs with low coal rank was formed, controlling the sand volume of proppant at 150–200 m3, increasing the proportion of fine sand to more than 80%, decreasing the ratio of sand to 15–20%, adopting the pre-fill fluid with appropriately increasing the proportion of activated water and the sand-carrying fluid with low guanidinium gel concentration, and increasing the distance of the proppant and the energy of fracture creation by rapidly raising the variable displacement to 12 m3/min; through the simulation of the discharge dynamics and desorption seepage of thick reservoirs of JM4 well. By simulating the discharge and recovery dynamics of JM4 well and calculating the theory of desorption and seepage in thick reservoir, the results show that the radius of plane pressure conductivity of this well is 55-85 m/MPa, and the contribution of gas production mainly comes from the reformed area, accompanied by obvious gas–water anisotropy, while the gas–water anisotropy of seepageable flow and un-reformed area is not obvious.