Objective:To summarize the experience in the diagnosis and treatment of insulinoma. Methods:The clinical materials of 404 cases of insulinoma treated in Peking Union Medical College Hospital between 1953 and 2007 were analysed retrospectively. Results:The diameter of 79.6% tumors was less than 2cm.36.2% tumors were located in the head of the pancreas,282% in the body,35.6% in the tail.18 cases (4.5%) had malignant tumors.34 cases (9.0%) were with multiple insulinomas.960% patients had Whipple’s triad and the ratio of insulin to glucose was greater than 0.3 in 89.6% patients. The positive rates of adjuvant examinations for localization before operation were transabdominal Ultrasound 36.8%,CT 24.7%,Enhanced CT 66.7%,Multislice spiral CT pancreatic perfusion 92.7%,MRI 31.6%,Somatostatin receptor scintigraphy 33.3%,Endoscopic Ultrasound 79.1%,Selective Angiography 84.6%,PTPC 88.1%and ASVS 87.0% respectively.The positive rates of Fine needle aspiration biopsy and intraoperative Ultrasound were 89.2%,and 90.0% respectively.73.1% patients could be cured by enucleation of tumor. Conclusion:Multislice spiral CT pancreatic perfusion came to be the preferred preoperative examination for localization of insulinoma.With the minimally invasive techniques further applied in pancreatic surgery,laparoscopic operation are suitable for some cases of insulinoma.In order to prevent missing tumors,however,open abdominal operation is adviced for the multiple insulinomas so as to explore more carefully.