Direct injection of oxy-coal combustion flue gas into coal reservoirs is viable to mitigate CO2, SO2 and NOx emissions, with the simultaneous benefit to improve coalbed methane (CH4) recovery. To study the feasibility of this technology, the displacement process of adsorbed CH4 on coals by SO2/CO2 binary mixture injection, termed as SO2/CO2-ECBM, was investigated in laboratory. The results show that the adsorption amount of CO2 on coals at displacement equilibrium state for SO2/CO2 injection slightly decreases compared with that for pure CO2 injection. The total adsorption amount of SO2/CO2/CH4 shows approximate linear correlation with coals' micropore parameters. However, a downward parabolic relation is found between the adsorption amount of CO2 and micropore parameters. In comparison with CO2 injection, the molar composition of CH4 in the bulk phase rises while that in the adsorbed phase drops at displacement equilibrium state for SO2/CO2 injection. All these changes in molar compositions of CH4 in the two phases lead to more CH4 molecules desorption from coal matrix, and demonstrate that implementing SO2/CO2-ECBM can achieve superior CH4 recovery. XPS characterizations confirm that the injected SO2 contained in SO2/CO2 occupying the oxygen-containing functional groups, i.e. C-O and C=O on coals, is the main interaction mechanism between SO2 and coals. This chemisorption effect may account for the enhanced CH4 recovery via SO2/CO2 injection. To summarize, injection of SO2/CO2 rather than CO2 into coal seams has potential to generate higher CH4 recovery and mitigate SO2 and CO2 emissions into the atmosphere.