In this study, the field injection and production process were simulated using an online visual nuclear magnetic resonance (NMR) technique to investigate CO₂-enhanced coalbed methane recovery (CO₂-ECBM) through physical experiments, and the impacts of pressure, temperature, injection volume, water saturation, and pore characteristics on CH₄ desorption and displacement were analyzed. The results indicate that increasing injection pressure from 10 MPa to 20 MPa can reduce CH₄ adsorption capacity by 32.6%, demonstrating a significant role of pressure on enhancing the competitive adsorption of CO₂. Temperature elevation can linearly decrease CH₄ adsorption by 30%, while higher CO₂ injection volume can reduce CH₄ desorption by 27.6%, conforming to a linear relationship. Additionally, increased water saturation can reduce CO₂ displacement efficiency, with a decline in CO₂ adsorption capacity as water saturation increases, indicating that occupation of adsorption sites by water molecules inhibits the gas displacement process. Larger pore diameters can enhance CH₄ adsorption capacity, and CO₂ displacement efficiency can be improved progressively as pore size increases. The experimental results confirm the preferential adsorption of supercritical CO₂ in deep coal seams, which is governed by multifactorial coupling mechanisms.