To investigate the safety and efficacy of percutaneous left atrial appendage closure (LAAC) in nonvalvular atrial fibrillation patients (NVAF) with left atrial spontaneous echocardiographic contrast (LA SEC). A total of 95 NVAF patients treated in the Department of Cardiology of Ningbo First Hospital from July 2018 to June 2019 were enrolled in this study. The study population was divided into two group according to the presence or absence of LA SEC detected by transesophageal echocardiography (TEE). TEE was scheduled 45 days post-procedure to detect device-related thrombus (DRT). Stroke and bleeding events were recorded during follow-up. Periprocedural complications and follow-up results were compared between the two groups. LA diameters were smaller in non-LA SEC group than LA SEC group ((44.0±7.4)mm vs (47.3±6.6)mm, =0.033). Watchman device was successfully implanted into all the enrolled patients. No death, transient ischemic attack (TIA)/stroke, device embolization and major bleeding events occurred. Fifty patients (90.2%) in LA SEC group and 31 patients (91.2%) in non-LA SEC group finished TEE follow-up 45 days post-procedure. No device-related thrombus was detected in non-LA SEC group, while 2 cases (6.5%) were detected in LA SEC group, but there was no significant differences in the incidence between the two groups (=0.127). The LA SEC group and non-LA SEC group were followed-up for (12.3±3.8) months and (12.9±3.3) months, respectively; and there was no significant differences in the incidence of death, TIA/stroke, major and minor bleeding events between two groups during the follow-up (all >0.05). LAAC in NVAF patients with LA SEC was safe and effective. However, the incidence of DRT was slightly higher.