Abstract: Deep coalbed methane (CBM) is a new field of hydrocarbon exploration with huge resource potential. In 2021, a great breakthrough was achieved in the exploration and development of CBM at depths greater than 2 000 m in the Daning-Jixian block on the eastern margin of Ordos Basin. The initial gas production from Well Jishen 6-7P-01 reached 10×10⁴m³/d, marking the beginning of large-scale exploration and development of deep CBM in the basin. The lack of a systematic study on targeted pore characteristics has restricted the efficient development of deep CBM in the study area. Based on the test data of cores, scanning electron microscopy, full-diameter CT scans, reservoir properties, low-pressure CO₂ adsorption, low-pressure N₂ adsorption, and high-pressure mercury injection, the paper systematically analyzes the reservoir characteristics and pore structure of the No.8 coal seam in Taiyuan Formation of Daning-Jixian block. The results indicate that:(1) The No.8 deep coal reservoir formed in waterlogged forest and swamp with lagoon facies. Bright and semi-bright coal are mainly found in the study area, with a high organic matter thermal maturity (average R_o of 2.81%). Cleats and fractures are well developed but often filled with secondary minerals, resulting in a low effective fracture ratio. (2) The of the No.8 deep coal seam has poor reservoir properties, of which the matrix porosity ranges from 3.60% to 6.11%, averaging at 3.65%, and the matrix permeability ranges from 0.001 mD to 0.060 mD, averaging at 0.016 mD; it is classified as an ultra-low porosity and ultra-low permeability reservoir. Micropores are the dominant pore type, followed by macropores, while mesopores are poorly developed. Micropores with the specific surface area ratio exceeding 99% serve as the main storage space for adsorbed methane. (3) Compared with the No.8 mid-shallow coal reservoir and the Longmaxi Formation shale reservoir in Sichuan Basin, the No.8 deep coal reservoir has lower permeability. This is primarily due to less effective cleats and fractures, and more micropores with poor connectivity. Based on this understanding, a shift in reservoir stimulation strategies in combination with super-large-scale volume fracturing techniques have significantly increased gas production from the No.8 deep coal reservoir and effectively guided the exploration and development of deep CBM in the study area.