Abstract: Laboratory test of reservoir CO2 flooding of Huan 50 block has been introduced in this paper. By comprehensively considering oil reservoir characteristics, reservoir characteristics and crude oil properties, the principles and conditions of reservoir CO2 flooding screening have been established. Through the indoor physical model test, the cover sealing, fault impermeability, reservoir adaptability and fluid adaptability research have been carried out. The results indicate CO2 flooding is fit for Huan 50 block and the CO2 development can be implemented.