Objective To study the expression of CD34 on hematopoietic stromal cells of mice and discuss the significance.Methods Using the methods of RT PCR, blot hybrization and In Situ hybrization to analysis the expression of CD34 on ① bone marrow stromal cells of BALB/c mice in primary culture and passage culture,② hematopoietic stromal cell line NIH3T3.Results The passage cultrual bone marrow stromal cells have a high expression of CD34, secondly is NIH3T3 cells, the expression little.Conclusion The CD34 antigen was also expressed on hematopoietic the different cells may be related to the cell proliferation, cell component and the ability to support ex vivo hemtopoiesis.