Objective To investigate the effect of Angelica polysaccharides on the balance of Th17 / T-regulatory( Treg) cells and the expression of related inflammatory factor proteins in the bone marrow of mice with aplastic anemia. Methods 50 male BALB / c mice were randomly divided into a normal group, model group, cyclosporine A(CsA) group,and angelica polysaccharide low-(APS-L) and high-dose(APS-H) groups. A mouse model of aplastic anemia was prepared by combining irradiation with allogeneic lymphocyte infusion. After modeling, the mice were orally administered with corresponding drugs for 28 days. The general condition, weight changes, and spleen index of the mice were observed.Blood samples were taken to test for changes in basic hematological parameters of peripheral blood, and hematoxylin and eosin staining was used to evaluate the pathological changes in mouse bone marrow tissue. An ELISA method was applied to detect bone marrow TGF-β1. The expression levels of proteins such as IL-10, IL-17A, and IL-6 were analyzed, and flow cytometry was used in detecting the bone marrow Th17 / Treg cell ratio. Results Compared with the normal group, the model group mice showed clumsiness during activity; lethargy; pale eyelids, lips, and ears; and reduced food and water intake. Both body weight and spleen index were significantly decreased. Peripheral red blood cell, white blood cell, and platelet counts and hemoglobin concentration were significantly reduced. A disordered bone marrow tissue structure and significantly reduced proliferation of hematopoietic tissue were seen. The expression of IL-17A and IL-6 proteins was significantly upregulated, and the expression of TGF-β1 and IL-10 protein was significantly downregulated. The proportion of Th17 cells in bone marrow significantly increased, the proportion of Treg cells significantly decreased, and the ratio of Th17 / Treg cells significantly increased (P<0. 01) . Compared with the model group, the general condition of the APS-L and APS-H groups improved, showing an increase in food and water intake; a significant increase in body weight and spleen index; a significant increase in peripheral red blood cells, white blood cells, platelets, and hemoglobin concentration ( P<0. 05 ) ; an improvement in bone marrow tissue structure; and an increase in hematopoietic tissue proliferation (P<0. 05) . The expression of IL-17A and IL-6 proteins was significantly downregulated. The expression of TGF-β1 and IL-10 protein was significantly upregulated ( P<0. 05 or P<0. 01) . The proportion of Th17 cells in bone marrow significantly decreased, the proportion of Treg cells significantly increased, and the ratio of Th17 / Treg cells significantly decreased ( P<0. 01 ) . Conclusions Angelica polysaccharides can improve bone marrow hematopoietic function in aplastic anemia mice, and its mechanism of action may include the regulation of Th17 / Treg cell balance.