Astragaloside IV (AS-IV) is one of the main pharmacologically active compounds found in Astragalus membranaceus . AS-IV has protective effects against ischemia–reperfusion injury (IRI), but its mechanism of action has not yet been determined. This study aims to investigate the effect of AS-IV on IRI and its effect on the phosphadylinositol 3-kinase (PI3K)/Akt/heme oxygenase (HO-1) signaling pathway through in vitro experiments. Firstly, a cell culture model of myocardiocyte hypoxia–reoxygenation (H/R) injury was replicated. After AS-IV treatment, cell viability, reactive oxygen species (ROS) levels, as well as the content or activity of the cellular factors lactate dehydrogenase (LDH), superoxide dismutase (SOD), malondialdehyde (MDA), interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), were measured to evaluate the effect of treatment with AS-IV. The effect of AS-IV on HO-1 protein expression and nuclear factor E2-related factor 2 (Nrf2) and Bach1 protein expression was determined by Western blotting. Finally, a reversal of the effect of AS-IV treatment was observed following co-incubation with a PI3K inhibitor. Our results show that AS-IV has good protective effect on H/R injury and has anti-oxidative stress and anti-inflammatory effects. It can regulate the expression of Nrf2 and Bach1 proteins in the nucleus and promote the expression of HO-1 protein, while a PI3K inhibitor can partially reverse the above effects. This study suggests that the PI3K/Akt/HO-1 signaling pathway may be a key signaling pathway for the anti-IRI effect of AS-IV.