Abstract: OBJECTIVE To explore the effect of Xuefu Zhuyu decoction on pulmonary vascular remodeling in hypoxic pulmonary hypertension(HPH) rats and its related mechanism. METHODS Forty ♂ SD rats were randomly divided into normal control group, model group, Xuefu Zhuyu decoction group, NVP-BEZ235 group, and drug combination group, with 8 rats in each group. The HPH rat model was established by using low pressure and low oxygen. Pathological changes of pulmonary arterioles were observed by HE staining. The content of collagen fibers in pulmonary arterioles was measured by Masson staining. The expression of proliferating cell nuclear antigen(PCNA) was detected by immunohistochemical method, and the expressions of p-AKT, AKT, p-mTOR, mTOR and PCNA were detected by Western blotting. RESULTS Compared with normal control group, the walls of pulmonary arterioles thickened with the lumen narrowed in model group. The content of collagen fibers and the expressions of PCNA, p-AKT, p-mTOR were increased(P<0.05 or P<0.01). Compared with model group, in all treatment groups, pulmonary vascular remodeling was alleviated in varying degrees, the content of collagen fibers significantly reduced(P<0.01), and the expressions of PCNA, p-AKT, p-mTOR were decreased(P<0.05 or P<0.01). Compared with Xuefu Zhuyu decoction group, the content of collagen fibers reduced(P<0.05) and the expressions of PCNA, p-AKT, p-mTOR were decreased(P<0.01) in drug combination group. CONCLUSION Xuefu Zhuyu decoction can alleviate pulmonary vascular remodeling in HPH rats, decrease the content of collagen fibers in pulmonary arterioles and the expression of PCNA. The mechanism may be relevant to inhibiting PI3K/AKT/mTOR signaling pathway.