Abstract: To study the effects and mechanisms of <em<Juglans mandshurica maxim</em< extracts (HT) on anti-tumor and immunoregulation in mice, the experimental model of tumor-bearing mice was settled. HT performance of tumor inhibition rate, immune organs index, phagocytic function of macrophage, T lymphocyte proliferation, levels of IL-2 and TNF-α in serum and immune functions were tested on the basis of decided model. In addition, the effects of HT on peripheral blood cells were examined in immunosuppressed mice model. Experiment showed that, compared with the model group, HT could inhibit significantly tumor expansion and improve immune organs index. For the subject group with high-dose HT, the tumor inhibition rate was 54.6%, the phagocytic function of macrophage and T lymphocyte proliferation were enhanced, as well as the levels of IL-2 and TNF-<em<α</em< (<em<p</em<<0.050~0.001) were promoted. Moreover, HT could prolong exhausted swimming time and hypoxia tolerance time of the subjects, and increase leukocyte (<em<p</em<<0.050~0.001) of mice. It is obvious that HT has the prominent effects on inhibiting tumor proliferation and regulating immune functions.