Based on the mechanism of coalbed methane recovery by CO2 injection, starting from the experiments simulation studies and production practice, the influence factors of coalbed methane recovery by CO2 injection was analyzed. The study found that the main influence factors were as followings: the conditions of coal quality, water, injection pressure and rate of CO2.The gas injection process was affected by the different types, contents and distribution characteristics of the minerals in the coal and the water in the coal seam. Without external water supply in the state of free water, the higher content of carbonate mineral in coal was, the higher coalbed methane recovery was. The higher the gas injection pressure was, the better coalbed methane seepage channel output was. In a certain time, the methane stripping ratio increased with the increase rate of CO2 injection. By using analytic hierarchy process on the sensitivity analysis of the different factors, the results showed that the weighting coefficient of coal quality conditions was 0.55. Coal quality condition played a main role in the process of gas injection.