CO2 injection can reduce permeability in coal seams, affecting methane recovery. The study quantified these effects using mathematical models. Results show that higher CO2 levels increase permeability decrease, while lower CO2 levels lead to greater permeability recovery pressure. The Langmuir volume constant of CO2 influences these parameters, with higher constants resulting in larger permeability decrease coefficients. These findings can help adjust CO2 injection pressures for enhanced methane recovery in coal seams.