Abstract: Objective: To investigate the isolating culture and characteristics of endothelial progenitor cells(EPCs) derived from rat bone marrow.Methods: The EPCs of rat bone marrow were cultured by second adherent amplification in vitro.The capacity of the cells' proliferation was observed daily.These cells were performed immunofluorescence staining to detect the expression of CD133,CD34,Flk1 and CD31.The capability of forming blood vessels was observed through three-dimensional cultured cells.Results: Cell colony-forming units(CFUs) appeared at the 4th day.At the center of CFUs,cells were round,but around the CFUs,cells were fusiform shaped.Up to the 10th day,cells covered the bottom of the bottle like cobblestones.The proto-passage EPCs expressed CD133,CD34 and Flk1.And the 2nd passage cells expressed CD34,CD31 and Flk1.The 2nd passage EPCs by three-dimensional culture manifested sprouted EPCs and formed tube-like structures in collagen.Conclusions: EPCs can be gained from bone marrow through proliferation of cells ex vivo and these cells has the capability of forming blood vessel.