Abstract: Alzheimer's disease (AD) is a common neurodegenerative disease, but its underlying pathogenesis remains ambiguous. Emerging evidence suggests that neuroinflammation plays a crucial role in the pathogenesis of AD. As an advanced imaging technique for clinical applications, PET molecular imaging permits the non-invasive visualization of in vivo neuroinflammatory processes in AD. This review provides an overview of the molecular basis of neuroinflammation in AD and summarizes recent progress in PET molecular imaging of neuroinflammation.