In order to reduce the occurrence of different degrees of CO₂ channeling during the CO₂ flooding in low permeability reservoirs，the low-permeability and heterogeneous plane-section cores were selected，and large cracks and micro-cracks were created in the cores. The anti-five-point method was used to carry out the water flooding and CO₂ immiscible flooding experiments.The development after water flooding were simulated. Two-stage sealing experiment were carried，which was CO₂ flooding after water flooding with modified starch gel plugging cracks andC₂H₈N₂ blocking gas channel. The experiment results showed that modified starch gel could block cracks in the formation，and the recovery rate of water flooding was 23.4%. Gas channeling occurred during the first CO₂ flooding，but gas channeling was still an important stage to enhance recovery. The recovery rate of first CO₂ flooding was 21.3% . C2H8N2 could block gas channeling effectively and increase the volume of the sweep. The recovery rate of second CO₂ flooding after C₂H₈N₂sealing was 15.0%. In the anti-five-point core physics simulation experiment，modified starch gel’s first-stage sealing after water flooding and C₂H₈N₂ second sealing after CO₂ flooding had 59.6% recovery rate，indicating obvious oil increment.