To study the effects of Vitamin C on proliferation and apoptosis of human cervical cancer cell lines Caski in vivo.Caski cell was treated with different concentrations of Vitamin C in vitro.MTT was used for the analysis of cell proliferation,the flow cytometry was performed to assay cell cycles and DNA fragmentation assay was used to identify apoptotic cells,Western blot was used to evaluate the expression of apoptosis-related protein Bcl-2,Bax,E6 and Caspase 3,fluorescent dye assay was performed to determine the changes in mitochondrial membrane potential.Vitamin C treatment inhibited the proliferation of Caski cells significantly in a dosage-and time-dependent manner.The results from flow cytometry analysis indicated that Vitamin C interfered with cell cycles and increased cell percentage in S phase,at the same time,the number of apoptotic cells increased significantly.After Vitamin C treatment,the typical phenomenon for apoptotic cells was observed and the contents of pro-apoptotic protein Bax in the cytosol were significantly increased,but the contents of anti-apoptotic protein Bcl-2 and E6 and caspase 3 were down-regulated.Vitamin C accompanied by a significant reduction in the mitochondrial membrane potential in Caski cells.The results showed that the Vitamin C inhibits growth and induces apoptosis of Caski cell lines.