ObjectiveTo explore the preoperative diagnostic value of endoscopic ultrasonography (EUS) for intraductal papillary mucinous neoplasms (IPMN). MethodsData of 62 patients with IPMN confirmed by pathology who underwent EUS before surgery from 2008 to 2018 in Peking Union Medical College Hospital were analyzed. Characteristics that could distinguish low-grade dysplasia (LGD), high-grade dysplasia (HGD) and invasive carcinoma (IC) were explored. A scoring system based on EUS findings was established to determine the preoperative pathology of IPMN by using logistic model. ResultsOf the 62 patients, 15 (24.2%) were diagnosed as having LGD, 20 (32.3%) HGD and 27 (43.5%) IC. Univariate analysis showed that the size of mural nodules and width of main pancreatic duct (MPD) were predictive factors for IPMN pathology. The possibility of higher pathological grading would increase 8% for every 1 mm increment in mural nodules. Multivariate analysis showed that only mural nodules≥5 mm (OR=7.31, 95%CI :2.49-21.40, P<0.001) was an independent risk factor to distinguish LGD, HGD and IC. Mural nodules≥5 mm, main pancreatic duct (MPD)≥10 mm and mural nodules ＜5 mm were assigned 2 points, 1 point and 1 point, respectively. The sensitivity, specificity, and area under receiver operator characteristic curve (AUC) of the EUS scoring system to distinguish benign and malignant IPMN were 0.830, 0.867, and 0.867, respectively. ConclusionPreoperative EUS helps to distinguish LGD, HGD and IC. The size of mural nodules and the width of MPD are vital risk factors to distinguish benign and malignant IPMN.