Abstract: The differences in gas content and their controlling factors in the deep coalbed methane (CBM) reservoirs of the Carboniferous-Permian strata in the Dacheng Uplift of the Bohai Bay Basin remain critical challenges in exploration and development efforts. This study analyzes gas content data from existing wells in the Dacheng Uplift and conducts numerical simulations. The results demonstrate that, the Dacheng Uplift exhibits a distinct "lower in the north and higher in the south" gas content distribution pattern in its Carboniferous-Permian coal seams, with gas contents in southern exploration wells generally exceeding 10 m³/t. Key controlling factors on coalbed gas content include reservoir temperature, pressure, water saturation, coal rank, pore characteristics. As coal rank (Ro) increases, methane adsorption capacity strengthens while free gas content decreases. Pore volume shows a significant positive correlation with gas content, whereas total porosity negatively correlates with coal rank (Ro). Increased ash content also leads to reduced total porosity. This study further constructs isothermal adsorption and free gas content prediction models for deep coal seams under the influence of reservoir pressure, temperature, coal rank, and apparent density. Model validation demonstrates good correlation between predicted results and experimental data, validating their applicability for estimating methane adsorption capacity in deep coal seams. Calculations reveal that methane saturation adsorption reaches a critical value of 14 m³/t at approximately 1100 m burial depth, while free gas content increases with depth before stabilizing. The critical burial depth for total gas content is around 1200 m, where gas content reaches 16 m³/t. Considering gas content, gas occurrence state, and burial depth comprehensively, the optimal development depth range for the Dacheng Uplift is identified as 1500-2600 m, where total gas content ranges between 14-16 m³/t with free gas占比 accounting for 25%-60%. This depth interval combines high gas content with mobile free gas advantages, representing the most favorable target zone for CBM exploitation in this area.The high gas content zones in the Dacheng Uplift are significantly influenced by coal rank and thermal maturity, with the gas generation capacity of the coal seams being the primary controlling factor for the enrichment of deep coalbed methane in this area.