Because of the high displacement efficiency and greenhouse gas emissions reduction, CO2 flooding technology is more and more attention from home and abroad, but in the process of CO2 flooding, there is a phenomenon of asphaltene precipitation which can cause the reduction of permeability. With actual crude oil in certain oilfield as an example, the regular pattern of asphaltene precipitation in the process of CO2 injection was studied, and the results showed that with the increase of injection pressure, amount of asphaltene precipitation increase gradually, and the core permeability decreases. For the influence of asphaltene precipitation, in the oil displacement process, the displacement efficiency decline.