The CO2 flooding technology has developed rapidly at home and abroad because it has the advantages of high efficiency，energy conservation and emission reduction. However，due to the high minimum miscible pressure of CO2 flooding in the bench-bar sandstones reservoirs of Shengli Oilfield，the miscible displacement is difficult to carry out and the oil displacement efficiency is low. As a result，a chemical system combining the double effects of synergism and solubilizing ability is designed，which can significantly reduce the minimum miscible pressure between CO2 and crude oil，and improve the effect of immiscible displacement. Firstly，the synergist DYJ-13 and the solubilizer S6 are screened by measuring the extraction amount of crude oil in CO2 and the dissolution amount of CO2 in crude oil. Furthermore，these two chemical agents are combined，and the effect of different proportions on the capability of crude oil extraction from CO2 is systematically investigated. The results show that with the increase of the mass fraction of DYJ-13，the synergistic factor increases and then decreases，and the solubilization factor do not change much，thus the optimal chemical system of DYJ-13∶S6=3∶7 is determined. Finally，the experiment of long slim tube displacement is carried out，and the minimum miscible pressure between crude oil and CO2 in the test area decreases from 31.65 MPa to 24.60 MPa，with a reduction of 22%，after adding the combined chemical system with a mass fraction of 3%. The developed chemical system has high application potential，and it is recommended to carry out single well tests.