In the development process of Block G in Dagang Oilfield, the air foam flooding system exhibits favorable oil displacement performance. However, affected by factors such as foam preparation technology, gas injection volume, gas injection rate and reservoir permeability heterogeneity, gas channeling is prone to occur during oil and gas production. To explore the mechanism of gas channeling in oil reservoirs and its impacts on oil and gas field development, experiments on the oil displacement performance of air foam flooding were conducted using a Brookfield viscometer, gas chromatograph and core flooding apparatus. The experiments investigated the effects of profile control agent types, gas injection modes and reservoir heterogeneity. Corresponding effective technologies for gas channeling control were also proposed. The results show that in the air foam flooding test with heterogeneous models, foam preferentially enters high-permeability layers, which increases seepage resistance and reduces water absorption index, thus achieving excellent effects of water control and oil production enhancement. Compared with conventional air foam flooding, the injection of Cr³⁺ polymer gel and hydrophobic associating polymer can effectively restrain gas channeling, and further improve the oil-increasing and water-reducing performance of air foam flooding. When the injection volume of gel plugging agent is 0.20 PV, the maximum increment of oil recovery factor reaches 15.23%; when the injection volume of polymer is 0.30 PV, the maximum increment of oil recovery factor is 11.35%.