Abstract： Objective To investigate the effect of different components of scorpion venom peptide (SVP)on stem and progenitor cells in irradiated mice. Methods Mice were exposed to 6.0 Gy X-rays. The number of colony-forming unit of spleen (CFU-S) was calculated at the 10th day after irradiation, and the methyleellulose culture method was used to detect the CFU-Mix on the irradiated mice at different time in vivo and in vitro. Results The study of SVP components in vivo showed that the number of CFU-S was significantly elevated by SVPⅣafter the irradiation, and CFU-Mix was also increased by both SVPⅣ and SVPⅤ. In vitro experiment showed that the number of CFU-Mix was much higher in SVPⅣ, SVPⅤ and cytokines groups respectively, as compared with control group. Both SVP Ⅳ and SVP Ⅴ had prominent effects in the formation of CFU-Mix when combined with cytokines. Conclusion SVP has a protective effect on the bone marrow hematopoietie stem and progenitor cells in irradiated mice.