To evaluate the effect of serum uric acid (SUA) level on left atrial phase function and mechanical stiffness (LAMS) in patients with paroxysmal atrial fibrillation by 2D-STI, and discuss the value of SUA level in clinical diagnosis and treatment of patients with atrial fibrillation. Methods Ninety patients with paroxysmal atrial fibrillation were enrolled in our hospital. According to SUA levels, SUA＞420μmol-1 were classified as the group with elevated SUA levels (n=41), and the rest as the group with normal SUA levels (n=49). At the same time, 27 healthy controls were included. The anterior-posterior diameter of left atrium (LAD), the largest volume of left atrium (LAVmax), the smallest volume of left atrium (LAVmin), the total emptying fraction of left atrium(LAtEF), the peak velocity of mitral blood flow in early diastole, and the early diastolic velocity (e') of mitral ventricular septal annulus and lateral annulus were measured, and the average velocity was calculated. 2D STI was used to evaluate left atrial reservoir strain (LASr), pipeline strain (LAScd), pump strain (LASct), left atrial reservoir strain rate (pLASRr), pipeline strain rate (pLASRcd), pump strain rate (pLASRct) and LAMS. 〖WTHZ〗Results Compared with the healthy control group, LAD, LAVmax and LAVmin in patients with paroxysmal atrial fibrillation increased (P＜0.05), while LATEF decreased (P＜0.05). Compared with the healthy group, the parameters of left atrium strain and strain rate showed that LASr, LAScd, LASct, pLASRr, pLASRcd and pLASRct in the normal SUA level group and the elevated SUA level group all decreased, and LAMS increased (P＜0.05). Compared with the normal SUA group, LASr, LAScd, LASct, pLASRr, pLASRcd, pLASRct were smaller and LAMS were larger (P＜0.05). Comparing the parameters of left atrial two-dimensional speckle tracking echocardiography of different genders, there was no significant difference between male and female groups in the healthy control group and SUA normal group (P＞0.05), while the LASr, LAScd and pLASRr of female group with increased SUA were lower than those of male group (P＜0.05), and there was no significant difference in LASct, pLASRcd, pLASRct and LAMS (P＞0.05).Correlation analysis showed that SUA level was negatively correlated with LASr, LAScd, LASct, pLASRr, pLASRcd, pLASRct and LAtEF (r=-0.36, P＜0.001; r=-0.30, P=0.001; r=-0.31, P=0.001; r=-0.31, P=0.001; r=-0.27, P=0.004; r=-0.29, P=0.002), which was positively correlated with LAmax, LAmin and LAMS (r=0.25, P=0.009; r=0.28，P=0.003;r=0.24，P=0.013 ). Conclusion SUA is negatively correlated with the left atrial phase function in patients with atrial fibrillation, and SUA is more sensitive to the left atrial function in elderly female patients