Abstract: Objective: To evaluate the effect of obesity on left atrial function in patients with essential hypertension by using two-dimensional speckle tracking imaging and real-time three-dimensional echocardiography. Methods:A total of 132 patients with essential hypertension and 114 controls with normal blood pressure were enrolled from Jiangning Hospital Affiliated to Nanjing Medical University from April 2022 to July 2023. According to the body mass index (BMI), they were stratified into six subgroups.The longitudinal strain and mechanical function index of left atrium were obtained by 2D-STI combined with RT-3DE technology, and the parameters above were analized and compared among the six groups. Results:Compared with the controls in the same BMI category,LASr and LAScd in hypertension patients were significantly decreased (P < 0.05)，with the aggravation of obesity,LASr, LAScd, LAEFt, LAEFp, LAEFa decreased in both hypertension patients and the controls (P < 0.05),Multivariate linear regression analysis showed that BMI was independently negatively correlated with LASr, LAScd, LAEFt,LAEFp and LAEFa (P < 0.05), but not with LASct (P > 0.05). Conclusion: Both Hypertension and obesity can lead to the impairment of left atrial function and obesity can aggravate the disfunction of left atrium in patients with hypertension.