Abstract: CO₂ channeling occurred too early in the pilot test of CO₂ flooding in Yaoyingtai oil field, which decreased its sweeping volume and production capacity. Low permeability fractured core models were generated by core cutting technique. Based on indoor experiments, the foam blocking ability and flooding performance were measured by core flooding experimental apparatus and EOR results of foam displacement following water and gas flooding were conducted. The mechanisms of different components in foam and EOR performance in low permeability fractured reservoirs were analyzed by numerical simulation. The results showed that foam could increase fluid flow resistance in the fracture, reduce liquid motility effectively and resistance factors were between 46 and 80; there was a foam apparent viscosity in the fracture that had an impact on the initial flow of foam. For the oil saturated fractured cores flooded by water and gas, oil recovery was increased by 26% and 35% respectively, and the mechanism of CO₂ foam EOR in low permeability fractured reservoirs was the transverse pressure between facture and matrix.