Heatstroke is a condition caused by overheating of the body that leads to severe central nervous system dysfunction. Although there have been numerous studies on the pathological process of heatstroke, effective treatment methods are lacking. Astragaloside IV can protect the brain from inflammation and brain damage in various inflammation-related diseases, but it has not yet been used clinically for the treatment of heatstroke. Therefore, the aim of this study was to explore the neuroprotective effect of Astragaloside IV on heatstroke-induced central nervous system damage and its mechanism. Brain injury model under heatstroke was established using artificial climate simulation cabin. By scoring neurological deficits, performing histological and immunofluorescence staining of microglia, and detecting cytokine levels, we determined that Astragaloside IV alleviated brain injury and neuroinflammation. To further explore the potential molecular mechanism, RNA sequencing was performed to investigate the differences in the brain. The results revealed that the PI3K/AKT pathway is involved. In vitro experiments further confirmed that Astragaloside IV can abrogate the phenotypic changes in microglia induced by heatstroke. Moreover, Astragaloside IV promotes the polarization of M2 microglia by activating the PI3K/AKT pathway. In summary, these results indicate that Astragaloside IV alleviates neuroinflammation and brain injury induced by heatstroke through the PI3K/AKT pathway. Astragaloside IV is a commonly used therapeutic agent in the clinic, but its use in the treatment of heatstroke-induced brain injury has not been explored. This study reveals that Astragaloside IV may be a new therapeutic agent for the treatment of heatstroke-induced brain injury.