Abstract： Aim To compare the influences of wood-cultured Ganoderma lucidum polysaccharides (Gl-PS-WC) and bag-cultured Ganoderma lucidum polysaccharides (Gl-PS-BC) on the proliferation activities of murine spleen lymphocytes in vitro, and investigate whether Gl-PS-BC can be substituted for Gl-PS-WC. Methods Mixed lymphocyte culture (MLC) reaction, lymphocyte proliferation induced by concanavalin A (Con A, 1 mg*L-1) or lipopolysaccharide (LPS, 5 mg*L-1), MLC reactions inhibited by immunosuppressive drugs, cyclosporine A (CsA, 0.1 mg*L-1), mitomycin (Mit C, 0.1 mg*L-1), or antitumor drug, etoposide (VP-16, 0.1 mg*L-1), were detected in the presence or absence of Gl-PS-WC and Gl-PS-BC in the concentration range of 0.2-12.8 mg*L-1. Results Two kinds of polysaccharides were shown to promote MLC in the range of 0.2-12.8 mg*L-1, increase lymphocyte proliferation induced by Con A or LPS and antagonize the inhibitory effects of CsA, Mit C or VP-16 on MLC. No significant difference was observed between these two kinds of polysaccharides in selected concentrations. Conclusion Gl-PS-WC and Gl-PS-BC showed similar effects on the proliferation activities of murine spleen lymphocytes in vitro.