Alzheimer's disease(AD)is the most common neurodegenerative disease,typically affecting individuals aged 65 and older.Mild cognitive impairment is generally regarded as a precursor stage of AD.The underlying molecular and cellular processes of AD can be visualized in vivo using PET/CT technology.Multi-modal imaging based on Aβ PET,tau PET,and FDG PET within the ATN framework can effectively characterize the core neuropathological features of AD.Many novel PET tracers have recently been developed and applied to deeply probe the pathophysiological dysfunction and internal environmental alterations in AD.Therefore,this review will summarize the recent advances of amyloid,tau protein,FDG,and neuroinflammatory PET probes in AD research within the ATN framework.