Abstract: Objective: To explore the comprehensive effect of Astragalus membranaceus extract (ASA) on the proliferation and apoptosis of H22 hepatocellular carcinoma cells and on the immune function of mice injected with H22. Methods: ASA was administered orally at doses of 0.031mg/g, 0.125mg/g, 0.5mg/g and 2mg/g, and the effects on growth and proliferation of H22 tumor cells in mice were evaluated by pathological observation, cellular PCNA immunohistochemical expression and flow cytometric proliferation index. Tumor cell apoptosis rate, expression of the apoptosis-related genes bcl-2 and bax, splenic CD4+ T lymphocytes, CD8+ T lymphocytes and the ratio of CD4+/CD8+ were quantitatively determined by flow cytometry. The phagocytotic function of macrophages was studied by observing peritoneal macrophages phagocytize chicken RBC. Results: After oral ASA administration at different dosages, no significant inhibiting effects on tumor growth or cellular proliferation were observed. Increased apoptosis rate, decreased Bcl-2 expression and increased Bax expression of H22 tumor cells in ASA treated groups could be found, but no significant correlation between ASA dose and these parameters were found. ASA administration could increase the splenic CD4+ T lymphocyte fraction, thereby increasing the CD4+/CD8+ ratio, and increase peritoneal macrophage phagocytosis rates. Conclusion: Oral administration of ASA could not significantly affect the growth or cellular proliferation of H22 tumor cells, but it could to some extent increase the apoptosis rate of H22 tumor cells in vivo. It could also improve cellular immunity of the mice bearing H22.