Objective To investigate the diagnostic value of endoscopic ultrasonography (EUS) for duodenal cysts.Methods Clinical manifestations, results of conventional gastroscopy and EUS, as well as follow-up, of patients with duodenal cysts were retrospectively analyzed.Results A total of 105 patients with duodenal cysts presented with no lesion-related symptoms, but displayed characteristic imaging changes under EUS, which could reveal the origin, size and nature of duodenal cysts, and differentiate it from other submucosal lesions.A maximum follow-up of 5 years showed no changes in duodenal cysts.Conclusion Duodenal cyst is a benign disease, and EUS plays a very important role in diagnosis of the disease.