This study aimed to evaluate the inhibitory effect of lentinan on the growth of rat C6 glioma cells in vitro. After C6 cells were treated with lentinan for 24, 48 and 72 h respectively, cell activity was detected using MTT assay. After the cells were conducted Annexin V/PI double staining or PI single staining, apoptosis and cell cycle were detected by a flow cytometry. The activities of C6 cells were significantly inhibited (P<0.01) by 20, 40 and 80 mg/L lentinan dose- and time-dependently. Meanwhile, 40 and 80 mg/L lentinan significantly increased apoptotic rate (P<0.01), significantly blocked cell cycle, increased the proportion of cells in G0/G1 phase (P<0.05), and reduced the proportion of S-phase cells (P<0.01). Lentinan can significantly inhibit the growth of rat glioma cells cultured in vitro, induce apoptosis and block cell cycle.