Objective：To determine the effect of erythropoietin（EP） on the proliferation of mesenchymal stem cells（MSCs） in vitro. Methods：Under serum free culture media, MSCs were incubated with different doses of EP for 24 h（0, 0.25, 0.5, 1, 2, 10 U／ml）, and then the proliferation of MSCs was measured by MTT assay. Cell circle stage was measured by flow cytometry assays after incubation of 10 U／ml EP for 72 h. Results：MTT assay showed that EP could enhance MSCs proliferation in a dose-dependent manner. There was significant difference among EP treatment groups and control group,except 0.25 U／ml group. The effects on the proliferation of MSCs was highest in 10 U／ml group. Furthermore,flow cytometry（FCM） assays showed that, compared with control group, EP could significantly decrease G0／G1 ratio, and increase S stage and G2／M stage ratio. Conclusion：EP could enhance MSCs proliferation in dose-dependent manner.