This study was aimed to investigate the inhibitory effects of sporoderm-broken ganoderma lucidum spores (GLS) on transplanted lymphoma in nude mice and its mechanism. The models of the subcutaneously transplanting tumor were established by N-methylnitrosourea-induced thymus T-cell lymphoma. The cellular apoptosis of tumor tissues in nude mice were observed by transmission electron microscopy (TEM), the mRNA expression of Bax, Bcl-2, Bcl-xl was determined by RT-PCR. The results indicated that the GLS had a certain anti-tumor effect, and the inhibitory rate was 45.8 with the dose of 4 g/kg (ig, once daily for 21 d). Apoptotic cells in lymphoma cells treated with GLS were observed by TEM. RT-PCR analysis showed that the expression of Bax was up-regulated, Bcl-2 and Bcl-xl were down-regulated in T-cell lymphoma cells. It is concluded that GLS can inhibit proliferation of lymphoma cells and induce the lymphoma cell apoptosis, the mechanism of which may be related with up-regulating the expression of Bax and down-regulating the expression of Bcl-2 and Bcl-xl.