Abstract: To study the effect of artesunate on the growth of human embryonic lung fibroblast HFL-I cells in vitro and provide experimental data for anti-fibrosis activity of artesunate. METHODS CCK-8 assay was used to determine the effect of artesunate on the growth of HFL-I cells in vitro. Apoptosis ratio was examined by flow cytometry (FCM). The mRNA level of Caspase-3, one of apoptosis related proteins，were assessed by RT-PCR. The expression of Caspase-3 protein was detected by Western blot. RESULTS Artesunate has a significantly inhibitory effect on the proliferation of HFL-I cells in a dose-dependent manner in vitro. Flow cytometry assay demonstrated a higher distribution in G1 phase of HFL-I cells with artesunate. And apoptosis rate of HFL-I cells was significantly increased in artesunate-treated group compared with control group (P<0.01). RT-PCR analysis showed the levels of Caspase-3 mRNA were significantly increased in artesunate-treated group, compared with control group. Western bloting also showed a significant enhancement of Caspase-3 protein levels in artesunate-treated group, when compared to control group. CONCLUSION Artesunate may exert marked anti-pulmonary fibrosis effect by up-regulating the mRNA and protein level of Caspase-3, which could induce the growth inhibition and apoptosis in HFL-I cells.