Abstract: The method of injecting carbon dioxide can effectively displace methane in coal and increase methane extraction rate. In order to study the characteristics of displacement process and the influence of different displacement pressure and flow rate on displacement process, using a self-made displacement experiment system with flow rate of 15, 10 and 5 mL/min were conducted respectively under different gas injection pressure such as 2.4, 1.8, 1.2 and 0.6 MPa. The experimental results show that the process of methane replacement in coal is the result of the joint action of carrying, displacement and dilution actions. In the initial stage of displacement, the concentration of CH₄ component decreased to 30% to 40%, which showed that the rolling played a leading role in the early stage of the process. The concentration of CH₄ in middle stage decreased to 5% to 10%, which indicated that displacement desorption played a leading role. In the later stage, the concentration of CH₄ decreased to 5% and tended to be stable, indicating that airflow dilution played a leading role. The larger the displacement flow, the weaker the displacement effect and the stronger the carrying and diluting effect. The pressure and flow rate of experimental process can effectively influence displacement effect.