Abstract: Most neurodegenerative diseases (NDDs) have been shown to be associated with the misfolding and abnormal aggregation of specific proteins in the brain. For example, abnormal aggregation of amyloid β-protein (Aβ) plaques and Tau protein are two important pathological features of Alzheimer's disease (AD). α-Synuclein (α-Syn) aggregates are biological markers of Parkinson's disease (PD) and dementia with Lewy body (DLB), while mutated huntingtins (mHTTs) serve as biological markers for Huntington's disease (HD). In the past few decades, positron emission tomography (PET) and diagnostic radiopharmaceuticals have been developed, leading to an increase in the use of PET imaging for early diagnosis of central nervous system diseases and the evaluation of related therapeutic drugs. In this article, the research progress of PET imaging agents targeting the above four types of protein aggregates was reviewed, aiming to provide ideas and references for further structural optimization and clinical application of related PET imaging agents.