Fractures and severe heterogeneity commonly exist in the low permeability reservoirs，which will cause varying degrees of gas channeling phenomena during CO2 flooding. In order to study the effect of heterogeneity and fractures on CO2 flooding efficiency，four experimental models of homogeneous model，heterogeneous model with various permeability ratios，high-capacity gas channeling model and fracture model were built in the laboratory to simulate the heterogeneity and fracture of the low permeability reservoirs. Waterflood and continuous CO2 flooding were conducted firstly，followed by gas channeling control experiments using different gas channeling control systems in different types of experimental models correspondingly. Experimental results showed that the oil recovery of continuous CO2 flooding had a power function negative correlation with permeability ratios and the gas channeling phenomena became more severe as the increase of heterogeneity，resulting in the poor displacement efficiency of CO2. Gas channeling control can be achieved using different gas channeling control systems in different types of experimental models. The gas channeling control in heterogeneous models with the permeability ratio of less or equal to 100 can be achieved by ethylenediamine system plugging high permeability layers，while gas channeling control in high-capacity gas channels and fracture can be achieved by modified starch gel and ethylenediamine.