The CO2 flooding technologies formed from research and practice in Zhongyuan Oilfield are systematically summarized in recent ten years，including CO2 flooding mechanism，suitability screening and evaluation technology，reservoir engineering optimization technology，injection and production engineering technology. The implementation results in the Lower Es1 reservoir of Pucheng Oilfield and Block Hu96 etc. are evaluated and analyzed，and the CO2 flooding experience for different types of reservoirs is summarized. Research results show that the CO2 can drive the residual oil after water flooding because of dissolving in oil spot and oil film for extra-high water cut reservoirs. The CO2 can displace the crude oil in the pore throat above 0.01 μm because of the small interfacial tension between the CO2 and crude oil and the small capillary resistance for the deep reservoir with low permeability. The field practice has proved that the relatively mature CO2 flooding technologies have been developed in the corrosion protection，profile monitoring，stratified injection and mobility control. Application of the CO2 flooding in the deep reservoirs with low permeability has obtained good results，which are in extra-high water cut stage. Because the CO2 flooding performance is not affected by temperature or salinity，it has great potential in the high temperature and high salinity reservoirs，which also provides references for the gas injection technology and practice in other types of reservoirs.