Excessive accumulations of reactive oxygen species (ROS) and amyloid-β (Aβ) protein are closely associated with the complex pathogenesis of Alzheimer's disease (AD). Therefore, approaches that synergistically exert elimination of ROS and dissociation of Aβ fibrils are effective therapeutic strategies for correcting the AD microenvironment. Herein, a novel near infrared (NIR) responsive Prussian blue-based nanomaterial (PBK NPs) is established with excellent antioxidant activity and photothermal effect. PBK NPs possess similar activities to multiple antioxidant enzymes, including superoxide dismutase, peroxidase, and catalase, which can eliminate massive ROS and relieve oxidative stress. Under the NIR irradiation, PBK NPs can generate local heat to disaggregate Aβ fibrils efficiently. By modifying CKLVFFAED peptide, PBK NPs display obvious targeting ability for blood-brain barrier penetration and Aβ binding. Furthermore, in vivo studies demonstrate that PBK NPs have outstanding ability to decompose Aβ plaques and alleviate neuroinflammation in AD mouse model. Overall, PBK NPs provide evident neuroprotection by reducing ROS levels and regulating Aβ deposition, and may accelerate the development of multifunctional nanomaterials for delaying the progression of AD.