To explore the laterality of SN+ area in patients with PD under TCS，and to further analyze its correlation with clinical data，in order to have a more comprehensive understanding of Parkinson's disease.Methods 81 patients with Parkinson's disease were collected，and the differences between SN+O and SN+N，SN+L and SN+R under transcranial ultrasound，and the correlation between SN+O and S/M and clinical data in patients with EOPD and LOPD were analyzed.Nonparametric test was used for difference analysis and spearman correlation was used for correlation analysis.Results The SN+O of PD was significantly larger than that of SN+N，and there was no significant difference in SN+ between left and right substantia nigra.The SN+O of early-onset PD was negatively correlated with the age of onset.Conclusion The area of SN+ on both sides of Parkinson's disease was asymmetrical under transcranial ultrasound.SN+O in Parkinson's disease was significantly larger than that in SN+N.The larger S/M often occurred in patients with early-onset PD rather than in patients with late-onset PD.Subgroup analysis showed that the age of onset of EOPD was negatively correlated with SN+O.SN+O and S/M in Parkinson's disease are not affected by age，disease duration，severity，autonomic nervous dysfunction and depression，but their stability as biomarkers needs to be further studied.