Abstract: Objective：To determine the differential expression of genes associated with cognitive impairment(CI) in Chinese Han patients of Xinjiang area with Parkinson′s disease(PD) and explore the pathogenesis of Parkinson′s disease associated with cognitive impairment(PD-CI). Methods：The peripheral blood samples of 3 Chinese Han patients with PD-CI and 3 healthy controls in Xinjiang area were screened by Illumina Microarray. The RT-PCR was used to confirm the differential genes that may associate with PD-CI in 35 PD-CI patients and 47 controls. Results：Compared with the healthy controls, 176 genes whose expressions changed more than 2 fold were found as the candidates of differentially expressed genes in the PD-CI patients. Among them, 68 genes were over expressed and 108 genes were down expressed. The results of KEGG pathway showed that the changes of dopaminergic and cholinergic synaptic signaling pathways in the PD CI group were significantly different from those in control group(P=0.046, P=0.005). RT-PCR revealed that the gene expression of ATP-binding cassette transporter A1(ABCA1) was significantly down regulated in the 35 PD-CI patients compared with the 47 subjects of control group(Z=-2.742, P=0.006). Conclusion：The pathogenic mechanism of PD-CI should associate with the metabolic abnormalities of cholinergic synapsis. ABCA1 gene may be a potential biomarker of PD-CI in Chinese Han patients of Xinjiang area.