Objective  To investigate the protective effects of astragaloside Ⅳ（ASⅣ）on chronic intermittent hypoxia (CIH)-induced cardiac injury.    Methods  Twenty-four male adult Sprague Dawley rats were randomly assigned to control, CIH, CIH+ASⅣ, and ASⅣ group, 6 rats in each group. Circular nitrogen and oxygen were filled to make oxygen concentration change between 9%-21% for the CIH treated rats. The exposure cycle was repeated every 3 minutes, 8 hours/day for 35 days. ASⅣ was given by intragastric administration daily before intermittent hypoxia exposure in the CIH+ASⅣ group and ASⅣ group. The control group and CIH group were given normal saline of the same quantity. Echocardiography was used to analyse cardiac function. Myocardial structure was assessed by HE and wheat germ agglutinin staining. The apoptosis of cardiomyocytes was detected by TUNEL assay. The levels of superoxide dismutase (SOD) and malondialdehyde (MDA) in heart were detected by commercial kits. Western blotting was used to evaluate the levels of Bcl-2, Bax, LC3, Beclin1, P62, and mammalian target of rapamycin（mTOR）.    Results  In the CIH group, the left ventricular ejection fraction (LVEF) and left ventricular internal diameter at end-systole (LVIDs) were inhibited, the myocyte cells showed disordered arranged, enlarged diameters and higher apoptosis rate. The MDA content was significantly elevated and the SOD activity decreased in CIH group when compared with those of control. What’s more, the expression level of Beclin 1 decreased while the P62 expression and the p-mTOR/mTOR ratio increased in the CIH group. Compared with the model group, the LVEF, LVIDs, SOD activity, LC3Ⅱ/Ⅰ ratio, and Beclin1 expression of rats in the CIH+ASⅣ group increased. The cardiomyocytes in the rats of CIH+ASⅣ group showed normal arrangement and diameters. The apoptosis rate, MDA content, P62 expression and the p-mTOR/mTOR ratio decreased in the CIH+ASⅣ group when compared with the CIH group.    Conclusion  ASⅣ can alleviate CIH-induced cardiac injury by promoting autophagy via mTOR.