Objective To determine the effect of dihydroartiminisin on the proliferation and phosphorylation of mitogen-activated protein kinase (MAPK) in SKOV3 and OVCAR3 ovarian cancer cell lines.Methods Methyl thiazolyl tetrazolium assay was performed to evaluate the anti-proliferative effect of dihydroartiminisin in SKOV3 and OVCAR3 cells,and Western blot was used to determine its effect on phosphorylation level of MAPK,including extra-cell regulated kinase (ERK)1/2 and p38 protein kinase,in the two cell lines.Results Dihydroartiminisin inhibited the proliferation of ovarian cancer cells in vitro,with a mean of 50% inhibition concentration (IC50) at 72 h of (9.0 ±1.4) μmol/L for SKOV3 and (5.5 ±1.2)μmol/L for OVCAR3 respectively. Compared to cells without dihydroartiminisin treatment,phosphorylation level of ERK 1/2 in SKOV3 and OVCAR3 cells treated with dihydroartiminisin decreased by 64.2% and 75.3% respectively (P＜0.05),while phosphorylation of p38 protein kinase in SKOV3 and OVCAR3 only decreased by 8.5% and 6.4% respectively (P ＞0.05).Conclusion Dihydroartiminisin can inhibit the proliferation of ovarian cancer cell in vitro, probably through down-regulation of the phosphorylation of ERK 1/2 in ovarian cancer cells.