Asphaltene precipitation is a common problem in the process of CO2 enhanced oil recovery project，which usually causes the pore throat plugging and wettability change of the reservoir. The formation damage and wettability change due to asphaltene precipitation was quantitatively evaluated under different CO2 injection pressures through core flooding test and NMR technique. The Experiment results showed that the viscosity and asphaltene content of the produced oil decreased and the asphaltene content of the residual oil increased with increasing injection pressure of CO2. When the injection pressure of CO2 was 9.1，16.2 and 24.1 MPa，the permeability reduction of core was 2.40%，7.41% and 8.32%，the mixed wettability index decreased 0.04，0.12 and 0.14，and the apparent contact angle increased 5°，12° and 19°，respectively. The higher injection pressure of CO2，the more serious asphaltene precipitation was，which would result in greater damage to the porosity and permeability of low permeability reservoir.