OBJECTIVE： To study the effects of Coriolus versicolor polysaccharides （CVP） on in vitro proliferation and apoptosis of murine melanoma B16 cell and its mechanism. METHODS： MTT assay was used to determine the survival rate of murine melanoma B16 cell after cultured with DMSO （negative control）， 0 （blank control）， 0.156， 0.312 5， 0.625， 1.25， 2.5， 5.0 and 10.0 μg/ml CVP for 48， 72 h， and the IC50 was calculated. Flow cytometry was used to determine the apoptotic rate of murine melanoma B16 cell after cultured with DMSO （negative control）， 0 （blank control）， 0.5 μg/ml CVP for 24， 48， 72 h. Quantitation Real-time PCR （qRT-PCR） was used to determine the mRNA expression of cell apoptosis-related gene P53， Bcl-2 and Fas in murine melanoma B16 cell after cultured with DMSO （negative control）， 0.5 μg/ml CVP for 48， 72 h. RESULTS： 0.156-10.0 μg/ml CVP could inhibit the growth of B16 cells， in concentration and time-dependent manner within 0.156-0.625 μg/ml； IC50 of B16 cells after cultured for 48 and 72 h were （0.32±0.01），（0.18±0.04） μg/ml. After cultured with 0.5 μg/ml CVP for 24， 48， 72 h， apoptotic rates of B16 cells were increased significantly， compared to negative control and blank control （P＜0.01）. After cultured with 0.5 μg/ml CVP for 48， 72 h， mRNA expression of P53， Bcl-2 and Fas were decreased significantly， compared to negative control （P＜0.01）. CONCLUSIONS： CVP can inhibit the proliferation and induce the apoptosis of B16 cells， the mechanism of which may be associated with the expression down-regulation of P53， Bcl-2 and Fas gene.