In order to improve the sensitivity and specificity of the diagnosis of Parkinson 's disease ( PD ), we selected three biomarkers, namely amyloid Aβ42, neurofilament light chain ( NF-L ), and α-synuclein ( α-syn ). On this basis, we designed the following composite parts, and overexpressed the corresponding three proteins in E.coli by means of genetic engineering. The accuracy of the obtained proteins was verified by ELISA, which can lay a foundation for the acquisition of specific antibodies and the construction of early screening kits. See the following table for detailed component composition. (Table 1).