Objective To observe the effect of Feiliuping Ointment on immune function of Lewis lung cancer bearing mice. Methods Flow cytometry was used to determine the number of DC,macrophage and phenotype in spleen of lung cancer bearing mice of different groups（blank group,Feiliuping Ointment group,model group）. Results There was no significant change in the number of DC in the blank group; the number of DC in the model group was decreased from 4.26% to 2.59%; the number of DC in the Lung Ointment group was decreased from 5.39%,4.83% and 4.15% at 14 d,21 d and 28 d,respectively. And at 28 d,there was significant difference compared with the model group（P<0.05）. Macrophages: in the model group,the number of M1 macrophages was increased gradually from 8.59% to 25.98%,meanwhile the number of M2 cells increased gradually from 0.92% to 5.42%,and the ratio of M1/M2 decreased from 9.34 to 4.79. In Feiliuping Ointment group,the number of M1 and M2 macrophages was increased more that of the model group at 14 d and 21 d,and at 21 d,they were 23.16% and 2.77% respectively,which were much higher relatively,but at 14 d,21 d and 28 d,M1/M2 ratios were 7.86,8.36 and 9.62,respectively. At 28 d,the number of both kinds of macrophages were decreased,but the M1/M2 value were also kept increasing,indicating that Feiliuping Ointment could promote the transformation of macrophages to M1 macrophages. Conclusion Feiliuping Ointment can regulate the number and expression of dendritic cells and macrophages in the spleen of tumor-bearing mice to make them as stable as possible,and then regulate the immune function of tumor-bearing mice in a balanced state,which may be one of its anti-tumor mechanisms.