Objective To investigate the correlation of LDL combined with LAD in left atrial thrombosis in patients with NVAF. Methods A total of 566 inpatients with atrial fibrillation from our hospital were collected. According to the exclusion criteria, 212 NVAF patients with transesophageal ultrasound or pulmonary venous CTV meeting the criteria were finally included. Finally enrolled patients were divided into two groups according to the results of transesophageal echocardiography or pulmonary venous CTV examination indicating whether there was thrombus in the left atrium: non-thrombotic group (n=178) and thrombotic group (n=34). The clinical data collected between the two groups were compared to analyze the risk factors of left atrial thrombosis in patients with atrial fibrillation, and explore the predictive value of LAD combined with LDL in left atrial thrombosis in patients with NVAF. Multivariate Logistic regression analysis was used to investigate the independent risk factors of thrombosis. ROC curve was used to analyze the prediction results of left atrial diameter and low density lipoprotein on left atrial thrombosis. Results Compared with the non-thrombotic group, the level of LDL, LAD, proportion of patients with non-paroxysmal atrial fibrillation, proportion of patients with heart failure, CHA2DS2-VASc score, fibrinogen, D-dimer and NT-proBNP in the thrombotic group were higher than those in the non-thrombotic group. The Left ventricular ejection fraction (LVEF) was lower than that in the non-thrombotic group. Univariate Logistic regression analysis of left atrial thrombosis in patients with elevated LDL, enlarged LAD, heart failure, non-paroxysmal atrial fibrillation, high CHA2DS2-VASc score, low LVEF and D-dimer were risk factors for left atrial thrombosis in patients with NVAF. Multivariate Logistic regression analysis of left atrial thrombosis showed that LAD enlargement, LDL increase and non-paroxysmal atrial fibrillation were independent risk factors for left atrial thrombosis in patients with NVAF. The area under ROC curve predicted by LAD for left atrial thrombosis in NVAF patients was 0.754 (95%CI: 0.679～0.830, P＜0.001). The area under ROC curve of LAD combined with LDL for predicting left atrial thrombosis in NVAF patients was 0.821 (95%CI:0.755～0.886, P＜0.001). The difference in area under ROC curve between the two was statistically significant (Z=2.344, P=0.019). Conclusion LDL combined with LAD is associated with left atrial thrombosis in patients with NVAF