Abstract: A great supportive and regulatory role has been played by the bone marrow microenvironment, esp. its component, stroma cells. Bone marrow stroma cells function cooperating with their surrounding ECM form a complicate network regulating differentiation and proliferation of hematopoietic progenitor cells.The radiation resistance exhibited by stroma cells is critical for the recovery of hematopoietic progenitor cells from residual damage.