Abstract: Objective To investigate the diagnostic value of conventional ultrasound in pancreatic serous cystadenomas (SCAs). Methods From Jan. 2005 to Dec. 2015, 39 patients with SCAs confrmed by pathology in our hospital were included and divided into four types: micro-cystic type (16 cases), macro-cystic type (12 cases), solid type (9 cases), and mixed-cystic type (2 cases). The ultrasonic manifestations and fnal diagnoses were retrospectively analyzed and compared between groups. Results The detection rate of pancreatic lesions using routine ultrasound was 100% (39/39), and the diagnostic accuracy was 56.4% (22/39). When compared the ultrasonic manifestations between the micro-cystic/solid type, macro-cystic type and mixed type, the tumor size of micro-cystic/solid type is smaller than that of mixed type or macro-cystic type (P< 0.05, respectively), and the border of micro-cystic/solid type is ill-defned whereas the mixed type or solid type is well-defned (P< 0.05, respectively). Conclusion Different types of SCAs have different ultrasonic manifestations, and the typical ones are easy to be diagnosed, while the atypical ones need to be diagnosed with assistance of other imaging techniques.