摘要Objective To observe the inhibitory effects of Radix Astragali (RA) on hypoxic structural remodeling of intraacinar pulmonary arteries (IAPA) and pulmonary hypertension (PHT).Methods　Sixty rats were divided into three groups: hypoxia group, hypoxia + RA group and normal control group. The rats of hypoxia group and hypoxia+RA group were fed in hypoxic environment under normal atmospheric pressure (10% O2, 10 h/day). On the 15 th and 30 th day of hypoxia, right ventricular systolic pressure (RVSP) and right ventricle hypertrophy index (RVHI) were measured and pulmonary vessel changes were studied under light and electron microscope and with morphometric analysis.Results　Compared with the result of hypoxia+RA group, RA could relieve IAPA wall cell injuries and dilate the constricted IAPA induced by hypoxia . RA could also inhibit hypertrophic changes in the tunica media and proliferation of adventitial cells of the IAPA and muscularization of nonmuscular arteries.Conclusion　By preserving the IAPA wall cells and dilating IAPA, RA may play an important role in inhibiting the remodeling of IAPA and preventing PHT.