Chemical flooding is an important enhancing recovery technology. Displacement mechanisms of different displacement agents were dissimilar There were some experiments finished to research the effect of chemical flooding. After evaluation of displacement systems, recoveries of all formulas were determined and the recovery contour diagram was completed. Recoveries obtained in experiments have been compared and influences of several chemicals on recovery have been analyzed. Experimental results showed that sweep efficiency should be more important in enhancing recovery than displacement efficiency. Oil recovery of formulas including alkali would not be good, because alkali led to low viscosity of displacement agents.