To investigate the influence of Shenqifuzheng injection on immune function in the course of chemotherapy of advanced gastric cancer patients. Methods: A total of 100 cases of gastric cancer patients (selected from June 2012 to June 2014) were randomly divided into observation group (n=50) and control group (n=50). The control group was treated with conventional chemotherapy and the observation group was given conventional chemotherapy plus Shenqi Fuzheng Injection. Both before and after treatment, the levels of CD3+, CD4+, CD8+, CD4+ / CD8+ cell ratio in peripheral blood of the two groups patients were recorded by Beckm Epics flow cytometry instrument produced by American Beckman company. Results: Total effect rate of the observation group was 82%, higher than that of control group (60%), and the difference was statistically significant (P<0.05). Adverse reaction rate of the observation group was 40%, and the level was among I ~ II. In contrast, the adverse reaction rate of the control group was 64%, and the level was among II ~ III. This difference shows statistical significance (P<0.05). The levels of CD3+, CD4+, CD4+ / CD8+ of the observation group were higher than those of the control group, whereas CD8+ levels were lower (P<0.05). Conclusion: Shenqi Fuzheng injection can improve immune function in patients with gastric cancer and improve their quality of life.