The type of coal facies is the key factor controlling the material composition and internal structure differences of coal. Ascertaining the controlling effect of coal on the heterogeneity of the pore structure of coal reservoirs is of great significance for the study of the adsorption/desorption and seepage laws of coalbed methane (CBM). Focusing on the Baode block, innovatively adopting the multi-scale coupling characterization technology system of "high-pressure mercury pressure-gas (N₂/CO₂) adsorption-fractal dimension", the high-precision quantitative characterization of the nano-micron scale full-scale pores of medium and low-rank coal in this area was achieved for the first time. It also revealed the control relationship between pore structure and coal phase, and optimized the advantageous coal phase area for CBM development. The main conclusions are as follows: the pore volumes of micropores, mesopores, mesopores and macropores decrease in a gradient manner, and the fractal dimension increases significantly with the decrease of pore diameter, indicating that the smaller the pore diameter, the higher the complexity of the pore surface and the adsorption potential, but the weaker the seepage capacity. The gelation index (GI) is positively correlated with the fractal dimension of micropore-mesopore, mainly affecting the adsorption capacity of coal reservoirs. The tissue preservation index (TPI) is positively correlated with the pore volume of medium and large pores, mainly affecting the seepage capacity of coal reservoirs. The pores of the coal reservoir in the water-overlying-wetland forest marsh phase show a three-peak distribution, with low fractal heterogeneity. Micropores and macropores develop synergically, which is the dominant coal phase of efficient adsorption-seepage integration. The open water marsh phase is second, and the low-level herbaceous phase and dry forest marsh phase are the worst. In the secondary development of CBM in the Baode block, the water-overlying-wetland forest marsh facies and the wide water area marsh facies areas should be regarded as the core geological target areas, while differentiated fracturing and transformation measures should be implemented for the coal reservoirs in the low-level herbaceous marsh facies and dry forest marsh facies areas.