The primary location where adsorbed gas-free gas is found in deep coalbed methane reservoirs is within the pores, and the pore structure of coal rock plays a significant role in determining the ultimate yield of deep coalbed methane. Given the intricate and varied characteristics of deep coal rock pore structures, a sophisticated multi-scale pore structure characterization technology for deep coalbed methane in the Ordos Basin has been developed. This technology involves various experimental methods such as CO2 adsorption, N2 adsorption, high-pressure mercury intrusion, micron CT, and nuclear magnetic resonance. Nuclear magnetic resonance experiments have revealed that the pore structure of deep coal rock is primarily characterized by a bimodal model, with a secondary three-peak model where the left peak dominates and the right peak is secondary. The predominant pore types are micropores, followed by macropores. Through an innovative approach that integrates the conversion relationship between transverse relaxation time T2 and pore diameter from nuclear magnetic resonance logging, the pore structure can be quantitatively assessed. Additionally, a pore classification scheme based on nuclear magnetic resonance logging has been established, categorizing deep coalbed methane pores into five groups: large pores, medium pores, small pores, micropores, and ultramicropores. The research findings demonstrate that the pore size distribution in deep coalbed methane reservoirs in the Ordos Basin is primarily composed of ultra-micropores, followed by macropores, with fewer micropores and less developed mesopores in small pores.