Abstract：Objective：To observe the effect of Yangzheng Huaji tang combined with chemotherapy on tumor markers and immune function in patients with colon cancer at middle-advanced stage. Methods：A total of 90 cases of patients with colon cancer at middle-advanced stage were randomly divided into the study group and the control group according to the random number table method，with 45 cases in each group. The control group was given FOLFOX4 chemotherapy，and the study group was additionally treated with Yangzheng Huaji tang based on the treatment of the control group. Both groups were treated for four weeks. The clinical effects in the two groups were compared； the changes of tumor markers including carcinoembryonic antigen(CEA)，carbohydrate antigen 19-9(CA19-9) and glycosphingolipid antigen(CA50) in peripheral blood as well as immune function before and after treatment in the two groups were compared. Results：After treatment，the total effective rate of clinical effect was 88.89% in the study group and 68.89% in the control group， the difference being significant(P＜0.05). After treatment， the indexes of CEA， CA19- 9 and CA50 in the two groups were decreased when compared with those before treatment， and the indexes of CEA， CA19- 9 and CA50 in the study group were lower than those in the control group，differences being significant(P＜0.05). After treatment，the indexes of CD4+ and CD4+/CD8+ in the two groups were increased when compared with those before treatment， and the indexes of CD8 + were decreased， differences being significant(P＜0.05). After treatment，the indexes of CD4+ and CD4+/CD8+ in the study group were higher than those in the control group，and the index of CD8+ was lower，differences being significant(P＜0.05). Conclusion：The therapy of Yangzheng Huaji tang combined with chemotherapy has a certain curative effect on patients with colon cancer at middle- advanced stage， which can improve their clinical symptoms， improve or control the disease， and enhance their immunity.