Effects of the compound of Ganoderma lucidum and Astragalus extracts on immunity and tumor of mice treated by cyclophosphamide (CTX) were investigated. The mice were given both compounds of Ganoderma lucidum and Astragalus extracts by gavage and CTX by peritoneal injection for two weeks after the mouse model bearing S180 tumor were produced. Then the antitumor effect, the thymus index, spleen index and the amount of white blood cells (WBCs) and red blood cells (RBCs) were observed and determined. Compared with the CTX group, the middle and high dose group of Ganoderma lucidum and Astragalus extracts significantly enhanced the effect of CTX on inhibiting the growth of S180 tumor (P<0.01), and prominently relieve thymic atrophy (P<0.01) and leucopenia (P<0.05, P<0.01) caused by CTX in mice. The compound of Ganoderma lucidum and Astragalus extracts showed synergy and attenuation of CTX in tumor therapy. Its efficacy was equivalent to that of single folium Ganoderma lucidum extract, which largely reduced the cost of single folium Ganoderma lucidum extract with a great economical value.