Objective To analyze the diagnostic value of two imaging examinations of multi-slice spiral CT (MSCT) and transesophageal echocardiography (TEE) for left atrial appendage thrombosis in patients with atrial fibrillation. Methods 195 cases of patients with atrial fibrillation who were diagnosed and treated in our hospital during the past year (January 2017 to January 2018) were selected. evaluated by computed tomographic angiography (CTA) and real-time three-dimensional transesophageal echocardiography (RT-3D-TEE) before catheter ablation treatment. The RT-3D-TEE test results were used as "gold standard", and the diagnostic efficacy of CTA was evaluated and compared, and the consistency of the two methods was analyzed. Results 14 cases of patients with positive left atrial appendage thrombus and 181 patients with negative left atrial appendage thrombus by RT-3D TEE examination. Taken RT-3D TEE test results as reference, the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of coronary CTA examination in the diagnosis of left atrial appendage thrombosis in patients with atrial fibrillation were 78.57%, 96.69%, 95.38%, 64.71% and 98.31% respectively. The two examination methods had high consistency in the diagnosis of left atrial appendage thrombosis in patients with atrial fibrillation (kappa value=68.79%, P<0.01). Conclusion Multi-slice spiral CT has high diagnostic efficacy in the diagnosis of left atrial appendage thrombosis in patients with atrial fibrillation, and it has good consistency with the results of echocardiography.