Abstract: Objective The components of deep coalbed methane (CBM), along with its isotopic composition and fractionation patterns, hold great significance for revealing the genetic types, occurrence characteristics, flow, and production patterns of CBM. Methods This study investigated the Shanxi and Benxi formations in the Daning-Jixian block, Ordos Basin. A range of analyses and tests were conducted, including field CBM desorption experiments on coal samples from the deep parts of both formations, continuous monitoring of wellhead gas from two production wells, physical property tests on the samples, organic petrological experiments, and geochemical analysis. Furthermore, this study analyzed the components and isotopes of both gas samples from natural desorption at the wellfield and produced gas from the production wells. In combination with the reported isotope data and gas-bearing property parameters of CBM worldwide, this study systematically delved into the carbon isotope fractionation patterns of methane during the desorption and production of deep CBM, as well as their geological implications. Results and Conclusions Coals in the Daning-Jixian block have entered the highly mature to overmature stage, characterized by a high fixed carbon content (average: 77.3%), high porosity (average: 7.4%), a strong adsorption capacity (average Langmuir volume: 23.5 m3/t), and a high measured desorbed gas content (average: 16.5 m3/t). During the field desorption of coal samples, the δ13C1 values of methane generally decreased initially and then increased, with isotope fractionation amplitudes ranging from 14.1‰ to 23.9‰. These results indicate the phased differences between the early-stage free gas release and the late-stage adsorbed gas desorption. In contrast, the δ13C1 values of methane in the wellhead gas of two production wells kept decreasing over time, suggesting that the produced gas is dominated by free gas presently. The isotope fractionation patterns of CBM during field desorption can be generally classified into types A, B, C, and D, with the δ13C1 values continuously increasing, decreasing initially and then increasing, increasing initially and then decreasing, and decreasing, increasing, and decreasing sequentially, respectively. These distinct types are primarily attributed to variations in the gas loss ratio and observation stage. Compared to shallow CBM, deep CBM generally exhibits higher carbon isotope fractionation amplitudes of methane (average: 21.1‰), higher δ13C1 values (average: −36.7‰), greater gas-in-place content (average: 21.8 m3/t), and higher free gas proportions (average: 19.9%). These characteristics are intimately associated with the features of deep CBM reservoirs, including their tight nature, high metamorphic grade, and high formation temperature and pressure. The origin identification results demonstrate that the deep CBM in the Daning-Jixian block is dominated by thermogenic gas, with partial gas samples subjected to secondary modifications by hydrothermal fluids or inorganic gas with a deep-seated origin. The results of this study deepen the understanding of mechanisms underlying the enrichment, preservation, flow, and production of deep CBM, serving as a guide for the selection of optimal sweet spots and production system optimization in the Daning-Jixian block and similar deep CBM-bearing zones.