Abstract: To investigate the distribution law of coal pore pressure and gas seepage driving mechanism during CO₂-enhanced coalbed methane recovery, experiments on CO₂ displacing CH₄ in coal were conducted using a self-developed isothermal and non-isobaric displacement test system. With the axial and confining pressures maintained at a constant 6 MPa and the gas injection pressure at 1.5 MPa, 2.5 MPa, 3.5 MPa, the volumetric strain of coal at different distances from the gas injection end, the variation characteristics of gas volume fraction at the outlet and the temporal and spatial evolution of the pressures of the two gases in coal were analyzed, the CO₂ displacement efficiency under different injection pressures was compared, and the gas seepage driving mechanism in coal was discussed. The results show that a higher gas injection pressure leads to greater coal swelling strain and larger deformation differences at various positions away from the injection end. Within the tested pressure range, the maximum strain difference among all volumetric strain measuring points reaches 0.860 6%. The displacement process can be divided into three stages: seepage displacement, replacement and carrying, and steady-state CO₂ seepage. Diverse dominant seepage mechanisms in each stage result in the nonlinear evolution of outlet gas volume fraction. After CO₂ injection, the coal pore pressure drops rapidly at first and then rises slowly. Once stabilized, the pore pressure presents a quadratic function distribution along the macroscopic gas seepage direction, and the pore pressure near the gas outlet end decreases by more than 80% compared with the injection pressure. The partial pressure of CO₂ increases continuously, and the variation of CO₂ partial pressure shows a more obvious hysteresis at positions farther from the injection end. The partial pressure of CH₄ in coal rebounds during its decline. At the injection pressure of 1.5 MPa, the CH₄ pressure in the middle part of coal exhibits the longest rebound duration and the largest rebound amplitude, accounting for 58.3% of the initial pore pressure. The rise of CH₄ pressure in coal pores inhibits its desorption capacity, resulting in a lower displacement efficiency under low injection pressure. The enhancement effect of pore pressure on gas flow capacity outweighs the weakening effect of coal matrix adsorption and swelling on gas seepage capacity. Higher gas injection pressure helps shorten the displacement time.