Objective   To explore the mechanism of Angelica Sinensis polysaccharide (ASP) promoting donor bone marrow transplantation (BMT) to reconstruct hematopoietic function of receptor mice by regulating bone marrow stromalcells (BMSCs).  Methods   Bone marrow mononuclear cells (BMMNCs) of male C57BL/6J mice aged 8-10 weeks were separated, purified and transplanted into female receptor mice of the same age. On the ninth day, receptor mice BMMNCs were separated, purified and transplanted again into female receptor mice. The transplanted receptor mice were divided into control group:  sham irradiation; Irradiation(IR) group: a whole-body irradiation with a total dose of 8.0 Gy X-ray; BMT group: the receptor mice treated in the same way as the IR group and transplanted BMMNCs (5×106 cells) from male donor via the tail vein; BMT+ASP group: the receptor mice treated in the same way as the BMT group, and injected ASP ［100 mg/（kg·d）×9］ by intraperitoneal route from the first day of transplantation. Changes in body weight and survival rate of mice were recorded during modeling, receptor mice BMMNCs were collected to detect sexdetermining region of Y(SRY) gene after building model, peripheral blood indexes, the number of BMMNCs in femur and histopathology of bone marrow were detected; BMSCs in receptor mice was separated and purified, BMSCs adhesion ability was observed, proliferation ability was detected by 5-ethynyl-2-deoxyuridine(EdU);The level of reactive oxygen species (ROS), the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) in BMSCs were detected; The levels of granulocyte-macrophage colony-stimulating factor (GM-CSF), stem cell factor(SCF), insulinlike growth factor 1(IGF-1) in culture supernatant of BMSCs were determined, CFU-Mix was counted after BMMNCs co-cultured with receptor BMSCs in each group for 48 hours;The expression of Notch signaling pathway related genes (Notch1, Jagged1, Hes1) in BMMNCs were measured by Real-time PCR.    Results   All mice in IR group were died,the body weight loss in BMT+ASP group was not obvious. The SRY gene was detected in the receptor female mice BMMNCs. Peripheral blood indexes and the number of BMMNCs were not significantly decreased in BMT+ASP group receptor mice,and bone marrow histopathological injury was reduced. ASP promoted the proliferation of BMSCs, decreased the contents of ROS and MDA, and increased the activity of SOD in BMSCs. ASP promoted the secretion of SCF, GM-CSF and IGF-1 in BMSCs, and increased CFU-Mix yield of BMMNCs co-cultured with receptor BMSCs. ASP increased the expression of Notch1, Jagged1 and Hes1 mRNA in BMMNCs.  Conclusion   The mechanism of ASP promoting receptor hematopoietic function reconstruction is related to reducing the oxidative stress damage of hematopoietic microenvironment, improving the secretion of hematopoietic growth factors in BMSCs, and regulating Notch signaling pathway.