Abstract: An inadequate understanding of the pore structure in coal reservoirs has long been a key constraint on the exploration and development of deep coalbed methane. While previous studies have recognized that coal pore structure parameters influence methane adsorption, a systematic investigation into the relative strength of these influences remains lacking. Here, experimental techniques such as field emission scanning electron microscopy, low-temperature CO₂ adsorption, low-temperature N₂ adsorption, high-pressure mercury intrusion porosimetry (MIP), and high-temperature high-pressure isothermal adsorption of methane were employed to establish a full-scale pore structure characterization method for coal rocks. Various pore volumes, specific surface areas, and fractal dimensions were calculated, and the impact of pore structure parameters on methane adsorption was studied. The results showed the following: (1) The coal rocks in the Linxing-Shenfu block developed a large number of plant cell cavities, stomata, mineral intercrystalline pores, and microfractures, with stomata being relatively well-developed and existing in clusters and nests; low-temperature N₂ adsorption experiments indicated that the pores in the coal rocks of the study area were mainly slit-type pores, ink bottle pores, and a mixture of the two; MIP experiments showed that the pore types in coal rocks were mainly type Ⅱ transitional pores. (2) The full-scale pore structure characterization results showed that the coal rocks in the study area exhibited macro- and micropores, with macropores accounting for more than 66.98%, followed by micropores; the specific surface area was dominated by micropores, accounting for over 96%; the fractal dimension of coal rock micropores was large, and the pore morphology was complex, followed by mesopores, with regular macropore morphology. (3) The adsorption amount of methane was mainly related to the pore volume and specific surface area of micropores and mesopores, and the fractal dimension had a weak influence on methane adsorption. In summary, the influence of pore structure parameters on methane adsorption capacity in the No. 8+9 coal seam of the Linxing-Shenfu block on the eastern margin of the Ordos Basin followed this descending order: micropore volume > micropore specific surface area > mesopore specific surface area > mesopore volume > micropore fractal dimension > mesopore fractal dimension > macropore-related parameters. This understanding provides critical guidance for the exploration and development of deep coalbed methane in the Linxing-Shenfu block.