Objective: To investigate the diagnostic value of tremor analysis in early stages of Parkinson’s syndrome, when the clinical symptoms of tremor onset are not unilaterally often able for a definite diagnosis to be made.Methods: We included 70 patients with unilateral tremor, under 45 years old and disease duration within 3 years enrolled in Peking University Third Hospital from January, 2014 to December 2015. We recorded clinical features, unified Parkinson’s disease rating scale (UPDRS)-Ⅲ, non-motor symptom (NMS) scores. Tremor analysis and transcranial sonography were performed for all the patients. Based on the results of tremor analysis, we arbitrarily divided the patients into 3 groups: (1) The patients with classical Parkinson’s syndrome manifestations on one side (25 cases); (2) The patients with classical Parkinson’s syndrome manifestations on both sides (15 cases); (3) The patients with no classical Parkinson’s syndrome manifestations (30 cases). The patients were monitored every 6 months to 3 years, until the final diagnosis was made.Results: There was no significant difference in age, gender distribution, Hamilton depression scale (HAMD) scores and H-Y scores among the three groups (P>0.05). The average UPDRS-Ⅲ motor scores of the three groups were significantly different (P=0.001), with 18.23, 18.79 and 14.67, respectively. The average scores of NMS were significantly different, with 15.81, 17.07 and 9.90, respectively (P<0.001). The positive rates of transcranial sonography (TCS) in the three groups were 48.0%, 60.0% and 26.67%, with no significant difference (P=0.702). After three years of follow-up, 35 patients (50%) met the diagnostic criteria of Parkinson’s disease of International Parkinson and Movement Disorder Society (MDS) in 2015, 19 patients (27.1%) met the criteria of idiopathic tremor, and 7 patients (10%) met the criteria of Parkinson’s plus syndrome. The sensitivity and specificity of tremor analysis for early diagnosis of Parkinson’s disease were 82.8% and 68.6%, respectively. Compared with TCS, the sensitivity and specificity of TCS were 65.7% and 62.9%. There were consistency (Kappa=0.568) and significant difference (P=0.031) between the two methods.Conclusion: Tremor analysis is sensitive and a superior way in identifying early Parkinson’s syndrome patients with tremor dominant manifestation. The combination of non-motor symptoms and transcranial sonography are also needed at diagnosis.