Grape seed proanthocyanidins (GSPs) have been receiving extensive attention due to their outstanding brain protection role in various disease models. This study aimed to explore the therapeutic effects of GSPs against acute high-altitude hypoxia-induced brain injury (AHHBI) and elucidate the underlying mechanism. SD rats and PC12 cells were employed in this study to establish in vivo and in vitro models of acute high-altitude hypoxia, respectively. In compared to mode group rats with hypobaric hypoxia exposure, GSP treatment significantly restored spatial learning and memory abilities of rats, reduced hippocampal inflammatory factor levels and NRLP3 inflammasome, and also enhanced hippocampal autophagy. In hypoxic PC12 cells, GSP treatment increased the survival rate of cells, improved cell morphology, reduced cell cycle arrest and apoptosis, and inhibited the activation of the NLRP3 inflammasome. Furthermore, GSP treatment enhanced autophagy and suppressed the PI3K/Akt/mTOR signaling pathway in hypoxic PC12 cells. However, autophagy inhibitor 3-MA compromised inhibitory effect of GSPs on NLRP3 inflammasome and the protective effects on hypoxic PC12 cells. Our study demonstrated neuroprotective effects of GSPs on rat model with high-altitude hypoxia exposure and PC12 cells experiencing hypoxic damage. The mechanism is related to the increase of autophagic flux promoted by GSPs, and the subsequent attenuation of NLRP3 inflammasome-mediated neuroinflammation. More effects and mechanisms of GSPs on the high-altitude hypoxia-induced brain injury are worthy to be explored in the future.