Abstract: In order to improve the oil recovery of CO2 flooding in low-permeability reservoirs and inhibit the CO2 channeling, the paper studies the influences of reservoir heterogeneity on gas channeling during CO2 flooding through laboratory experiments. On the basis of the experimental results, the characteristics of the oil production, ultimate oil displacement efficiency, gas breakthrough time, gas channeling time and pressure drop of different models are analyzed. The results show that vertically, the smaller the permeability contrast is, the later the gas channeling time will be; horizontally, the results of the model with high injection rate and low recovery factor are better than that with low injection rate and high recovery factor, that is, the higher the permeability at the inlet end，the later the CO2 channeling time, the better the oil displacement effect. The study result provides a beneficial support for the low permeability reservoir development in the Ordos basin