Cervi Parvum Cornu(CPC) is that the young horn of deer family and has been traditionally used as a medicine in Eastern. The purpose of present study was to investigate the effects of CPC on cell cycle progression and its molecular mechanism in human periodontal ligament cells (HPOLC). In cell proliferation assay, 1 ng/ml, 10 ng/ml, 100 ng/ml, 1 ㎍/ml and 10 ㎍/ml of CPC were used, all treatment groups increased the cell growth. Maximal cell proliferation was observed in cells exposed to 100 ng/ml of CPC at 4 day, and 10 ng/ml and 100 ng/ml of CPC at 6 days. S phase was increased and G1 phase was decreased in the group treated with 100 ng/ml of CPC in cell cycle analysis. The protein levels of cyclin D1 were not changed, but the levels of cyclin E, cdk 2, cdk 4 and cdk 6 were increased. The protein levels of p21, pRb were decreased as compared to that of control group, but the levels of p53 was not changed in the cells both treated with CPC Md untreated. These results suggested that CPC increases the cell proliferation and cell cycle progression in HPDLC, which is linked to an increased cellular levels of cyclin E, cdk 2, cdk 4 and cdk 6, and decreased the levels of p53, p21.