Nitric oxide synthase (NOS) and its product nitric oxide are involved in learning and memory functions. Increasing evidence shows that NOS plays an important role in the pathogenesis of Alzheimer’s disease, influencing β-amyloid protein (Aβ) deposition, neuroinflammation, oxidative stress, abnormal microglia activation, synapse damage, autophagy, abnormal mitochondrial function of nerve cells, and cerebral hypoperfusion or vascular endothelial cell injury. This review summarizes the recent evidence for the role of NOS in the pathogenesis of Alzheimer’s disease and provides new feasible targets for the prevention and treatment of Alzheimer’s disease.