The replacement method by CO_2 is regarded as a new approach to natural gas hydrate(NGH) exploitation method, by which methane production and carbon dioxide sequestration might be obtained simultaneously. In this study, CO_2 was used to recover CH_4 from hydrate reservoirs at different temperatures and pressures. During the CO_2–CH_4 recovery process, the pressure was selected from 2.1 to 3.4 MPa, and the temperature ranged from 274.2 to 281.2 K. Calculating the fugacity differences between the gas phase and the hydrate phase for CO_2 and CH_4 at different conditions, it has found rising pressure was positive for hydrates formation process that was helpful for the improvement of CH_4 recovery rate. Rising temperature promoted the trend of CH_4 hydrate decomposition for the whole process of CO_2–CH_4replacement.The highest recovery rate was 46.6 % at 3.4 MPa 281.2 K for CO_2–CH_4replacement reaction in this work. The present method, CO_2 was used to recover CH_4 from hydrate reservoirs at different temperatures and pressures. During the CO_2-CH_4 recovery process, the pressure was selected from 2.1 to 3.4 MPa, and the temperature ranged from 274.2 to 281.2 K. Calculating the fugacity differences between the gas phase and the hydrate phase for CO_2 and CH_4 at different conditions , it has found rising pressure was positive for hydrates formation process that was helpful for the improvement of CH_4 recovery rate. Rising temperature promoted the trend of CH_4 hydrate decomposition for the whole process of CO_2-CH_4replacement. highest recovery rate was 46.6% at 3.4 MPa 281.2 K for CO_2-CH_4replacement reaction in this work.