Many gastrointestinal stromal tumors( GISTs) were treated according to the guidelines in Japan. In this paper, our procedure of the local resection, minimal invasive surgery, the jejunal graft patching and an attractive new method of treating duodenal GISTs was reported. A 50-year-old woman with duodenal submucosal tumor was referred to our hospital. The gastrointestinal endoscopic examination, the computed-tomographic images, and the magnetic resonance images showed a 3.5 cm hyper vascular tumor at the posterior superior aspect of the pancreatic head. PET-CT images revealed accumulations only in the duodenal tumor. The endoscopic ultra-sonographic images and biopsy revealed that the tumor was positive for c-kit, as a periampullary GIST of the duodenum presumed pancreatic invasion. The authors showed a" conventional and safe" local resection and duodenoplastic surgical technique for duodenal GISTs, although some reports declared the efficacy of the Roux-en Y duodeno-jejunostomy in Japan.