Abstract: Objective To investigate the clinical value of intraoperative ultrasound guided precise positioning and enucleation of the functional islet cell tumor. Methods The clinical data of 20 patients with functional islet cell tumor who were admitted to the First Affiliated Hospital of Xinjiang Medical University from January 2005 to December 2011 were retrospectively analyzed. The method of precise positioning, surgical approach and prognosis of the patients were reviewed. Results The accurate rates of computed tomography (CT), magnetic resonance imaging (MRI) and transabdominal B ultrasound in detecting the position of the functional islet cell tumors were 12/18, 2/6 and 7/13, respectively, and the diameters of the tumors were (1.7±0.8)cm, (1.3±0.2)cm and (1.9±0.9)cm, respectively. The accurate rates of arterial stimulation venous sampling and pancreatic perfusion CT imaging were 100%, and the diameters of the tumor detected were (0.7±0.3)cm and (0.9±0.4)cm. The accurate rate of intraoperative B ultrasound examination was 14/14, and the diameter of the tumor was (1.5±0.6)cm. Routine surgery was carried out on 6 patients, and 2 patients were complicated with grade C pancreatic fistula, and 1 was complicated with grade A pancreatic fistula. Fourteen patients received precise enucleation of islet cell tumor, and 4 patients were complicated with grade A pancreatic fistula. Twenty patients were followed up. The general condition of the patients was good till April 2012, and no death, tumor recurrence and metastasis were detected. Conclusions Combination of pre and intraoperative imaging positioning could precisely locate functional islet cell tumor. If the distance between the tumor and main pancreatic duct is above 3 mm, precise enucleation of the islet cell tumor should be considered.