Non-valvular atrial fibrillation has seriously affected the quality of life of patients because of its high incidence, high disability rate and high recurrence rate. Accurate evaluation of the structure and function of left atrial appendage is of great importance in detection of its thrombus and in prediction for stroke events. Conventional imaging techniques, such as transesophageal echocardiography, transthoracic echocardiography, intracardiac echocardiography, CT and cardiac magnetic resonance imaging, and new technologies, represented by positron emission tomography/cardiac magnetic resonance imaging combined with new molecular targeted tracers, and computer fluid dynamics, are providing important objective basis for evaluating its structure and function and for detecting its thrombus. In this article, we reviewed the anatomy, function, imaging progress of left atrial appendage and its thrombus in patients with non-valvular atrial fibrillation.