Objective: To investigate the diagnosis and treatment of insulinoma (pancreatic β-cell tumor). Methods: We admitted and treated one case of insulinoma, and that case together with the data of 1 362 patients with insulinoma documented in the literature in China were analyzed. Results: Of the 1 363 patients, 1 286 cases (94.35%) showed signs of Whipple’s triad, and the insulin to glucose ratio (IRI/G) was calculated in 1 099 patients, which in 1 019 cases (92.72%) was higher than 0.3. The preoperative tumor detection by B-type ultrasound scan, CT, MRI, selective angiography (DSA), selective arterial calcium stimulation (ASVS), Endoscopic ultrasonography (EUS), percutaneous transhepatic portal catheterization (PTPC), somatostatin receptor scintigraphy (SRS) and intraoperative ultrasound (IOUS) plus palpation was 40.90% (418/1 022), 55.20% (457/823), 52.45% (96/183), 77.42% (247/319), 89.47% (34/38), 78.68% (48/61), 86.11% (62/70), 36.36% (8/22), and 93.97% (312/332), respectively. All patients underwent surgery, and 1 006 cases (73.80%) received tumor enucleation. All of them were diagnosed as insulinoma by postoperative pathology, 42 cases (3.08%) had malignant change, 98 cases (7.19%) had multiple lesions, 28.25% tumors were located in the head of the pancreas, 33.90% in the body of the pancreas, and 37.83% in the tail of the pancreas. Pancreatic fistula occurred in 276 patients (20.25%). Recurrence occurred in 16 benign cases and in 7 malignant cases after operation. Conclusion: Whipple’s triad and IRI/G higher than 0.3 can be used as the main evidence for diagnosis of insulinoma. Preoperative localization can be made by combination of different methods, and IOUS plus palpation is a simple and effective method for intraoperative localization. Enucleation is the major surgical treatment for insulinoma.