Objective To investigate the radioprotective effect of genistein (GEN) on murine bone marrow stromal cells (BMSCs). Methods Adult male mice were administered orally with GEN at 24 h prior to 6.0 Gy gamma irradiation. The number of CFU-F, the adherent capability of bone marrow cells (BMCs) to BMSCs adherence layer, and the expressions of cell adhesion molecules including vascular cell adhesion molecule-1 (VCAM-1), fibronectin (Fn), and laminin (Ln) on BMSCs cultured in vitro were detected, respectively. Results The number of CFU-F, the adherent capability, the expressions of VCAM-1, Fn, and Ln on BMSCs cultured in vitro in GEN-pretreated mice were higher and recovered more rapidly than those in mice without GEN-pretreatment. Light microscopy revealed that there was no significant difference in morphology of BMSCs in both groups after irradiation injury. Conclusion These observations suggest that radioprotective properties associated with GEN are largely a consequence of the reduction of damage, the induction of cell proliferation, and the promotion of adherent capability recovery in recipient mice. These changes may ultimately ameliorate bone marrow microenvironment and therefore accelerate the rebuilding of hematopoietic system after irradiation injury.