Parkinson's disease (PD) is the second most common neurodegenerative disorder worldwide, pathologically characterized by the loss of dopaminergic neurons in the substantia nigra and abnormal aggregation of α-synuclein (α-Syn). Current diagnosis primarily relies on clinical symptoms, and there remains a lack of early and specific biomarkers. Exosomes (EXs), as nanoscale extracellular vesicles capable of crossing the blood-brain barrier, carry molecular information such as proteins, nucleic acids, and lipids derived from the central nervous system, offering a new perspective for the diagnosis of PD. This article systematically reviews the significant potential of major biomolecules within EXs as novel biomarkers, as well as the challenges faced by current isolation techniques.