Parkinson’s disease (PD) is one of the most frequent neurodegenerative disorders. α-Synuclein was the first“PD gene”to be discovered. The involvement of α-synuclein in PD was first suspected after two different α-synuclein mutations were identified in two kindreds with autosomal-dominant PD. However, the discovery that α-synuclein is the major component of Lewy bodies-pathological hallmarks of PD, confirmed its role in PD pathogenesis. Pathological aggregation of α-synuclein might be responsible for neurodegeneration. Multiple factors have been shown to affectα-synuclein aggregation in vitro or in vivo. In addition, soluble oligomers of α-synuclein might be even more toxic than the insoluble fibrils found in degenerative diseases. So it is significant to investigate factors affectingα-synuclein aggregation, especially their accurate effects on the aggregation process.