Abstract: Objective To explore the imaging biomarker for early diagnosis and disease course monitoring of Parkinson disease (PD) in arterial spin labeling (ASL) technique. Methods Between July, 2014 and May, 2017, 23 patients with PD underwent magnetic resonance imaging (MRI) and ASL examinations in our hospital, including 13 in the early stage and 10 in advanced stages. Voxel-based analysis (VBA) was used to observe the regional cerebral blood flow (rCBF) characteristics in PD patients in different stages and three-dimensional continuous arterial spin labeling (3D CASL) was used to analyze the mean cerebral blood flow (mCBF). Results No significant difference was found in mCBF among PD patients in the early stage, patients in advanced stages and normal control subjects (P=0.30). Compared with the normal control group, the patients with early-stage PD had decreased rCBF in resting state mainly in the right superior occipital gyrus and the right superior frontal gyrus as revealed by VBA (P<0.001); the patients with advanced PD showed decreased rCBF mainly in the left precentral gyrus and the postcentral gyrus (P<0.001). The patients with advanced PD exhibited lowered rCBF in the right substantia nigra and the bilateral corpus callosum as compared with the early-stage patients (P<0.001). Conclusions VBA of ASL reveals rCBF alterations in association with the disease progression in PD patients, suggesting that this technique might provide assistance in identification of potential markers for early PD diagnosis and for monitoring the disease course.