In order to enhance shale gas recovery and store CO2 geologically, a development model of EGR by CO2 flooding in shale was proposed based on the thought of CO2 flooding oil. In order to investigate the potential of EGR by CO2 flooding, experiments in house and simulations of well pattern were carried out. Specifically, In-house study included experiments of adsorption isothermal between CH4 and CO2 and experiments of displacement seepage CH4 by CO2. The results of above experiments show that, adsorption capacity for CO2 was about three to five times than that for methane in shale formation at the same condition of pressure and temperature. In addition, gas recovery for adsorbed gas would be promoted more than 20% just because of CO2 flooding CH4 during displacement experiments in question. What was more, it was found that two main mechanisms for CO2 EGR in shale gas were concluded as molecular replacement by CO2 and keep of formation pressure by CO2 injection. Based on the results of experiments, considering difficulty of CO2 injection due to poor property of shale formation, this paper proposed a solution of CO2 injection in one well and production shale gas in two wells nearby based on the ideas from well pattern of water flooding oil in oil field. Distance between injection and recovery can be calculated by theory calculation, providing references for carbon dioxide flooding in the field.