Objective To determine the diagnostic value of transcranial sonography (TCS) in diagnosis of Parkinson’s disease (PD). Methods Fifty-eight PD patients and 60 patients with essential tremor (ET) admitted in our hospital from September 2013 to March 2014 were subjected in this study. They all received TCS examination. The area of the substantia nigra hyperechogenicity was measured and its ratio to the area of the whole midbrain area (S/M) was calculated. The sensitivity and specificity of TCS for the diagnosis of PD were determined by receiver operating characteristic (ROC) curve. Results The area of substantia nigra hyperechogenicity and the S/M ratio were greater in PD patients than in ET ones (P＜0.05). When the hyperechogenicity was used in diagnosis of PD, the area under the ROC curve was 0.801. The sensitivity was 74.1%, and the specificity was 76.7% when the critical value was set at 0.205. Conclusion TCS Is one of the valuable auxiliary examinations in diagnosis of idiopathic PD, and also of certain value in the differential diagnosis of PD with ET.