Amyloid β (Aβ) is a critical stimulator that promotes the progression of age-related macular degeneration (AMD). NLRP3 inflammasome activation induced by Aβ is estimated to be responsible for retinal pigment epithelium (RPE) dysfunction in such disease. Puerarin, one of the major active constituents of Kudzu root, has been widely used in the clinical treatment of AMD in China for decades; however, the detailed molecular mechanism remains far from clear. In this study, we investigated the protective effect and underlying mechanism of puerarin against Aβ1–40-induced NLRP3 inflammasome activation in LPS-primed ARPE-19 cells. The results showed that Aβ1–40 induced NLRP3 inflammasome activation mainly via triggering ROS-dependent oxidative stress, particularly lipid peroxidation, and endoplasmic reticulum stress in LPS-primed ARPE-19 cells; however, such effect could be significantly reversed by puerarin in a dose-dependent manner. Furthermore, the effect of puerarin was potentially mediated through activating Nrf2/HO-1 antioxidant signaling pathway and inhibiting Aβ1–40-induced phosphorylation of IRE1 and PERK as well as nuclear expression of ATF6α. Therefore, the significance of the current study is to reveal the novel mechanism of puerarin in the prevention of AMD.