Abstract: The occurrence state of coalbed methane (CBM) is one of the key factors influencing the resource assessment and the development efficiency of deep CBM. In order to elucidate the dynamic evolution laws of free gas and adsorbed gas within deep coal reservoirs, as well as their geological controls, thereby deepening the understanding of deep CBM accumulation processes, this study focuses on the No.8 coal seam of the Taiyuan Formation in the Daning-Jixian Block, Ordos Basin. Prediction models for free gas content, adsorbed gas content, in-situ porosity, and water saturation were established. These were integrated with a systematic reconstruction of the coal seam burial history, thermal history, thermal maturation, and reservoir pressure evolution, to investigate the dynamic evolution of gas occurrence states during CBM accumulation. The results indicate that the dynamic evolution of free and adsorbed gas during CBM accumulation in the study area can be classified into four stages: (Ⅰ) Late Permian-Early Jurassic: a period of rapid coal seam subsidence, accompanied by a sustained rise in adsorbed gas content and negligible free gas occurrence; (Ⅱ) Early Jurassic-Early Cretaceous: a stage of minor fluctuations in burial depth of coal seam, during which free gas content gradually increased, while adsorbed gas content exhibited oscillatory variations; (Ⅲ) Early Cretaceous-Middle Cretaceous: second rapid subsidence phase of coal seam, in which free gas content first decreases and then increases, with adsorbed gas content rising slowly; (Ⅳ) Middle Cretaceous-present: rapid uplift of coal seams, during which free gas content gradually decreases, while adsorbed gas content continues to increase. The findings of this study can provide a theoretical reference for favorable zone selection and efficient exploitation of deep CBM resources.