Pancreaticoduodenectomy, as a standard surgical procedure for malignant tumors of the head of the pancreas, ampulla and distal common bile duct, has brought the hope of clinical cure for these diseases.In the whole surgical process, the resection of the uncinate process of the pancreas is considered to be a major difficulty in the whole operation, which can affect the rehabilitation process and long-term prognosis. Two main methods have been developed around the dissection of the uncinate process of the pancreas. One is the Venous-first approach based on the portal vein-superior mesenteric vein axis. The other is the Artery-first approach that first explores whether the superior mesenteric artery is invaded by the tumor to judge resectable. The latter is gradually promoted in clinical practice because it can reduce intraoperative bleeding, reduce postoperative complications, and improve long-term prognosis. The intermediate approach is a surgical approach based on the Artery-first approach and adapted to the layout of the robot arm. The area between superior mesenteric artery and superior mesenteric vein was used as an intermediate area to treat the uncinate process of the pancreas in order to reduce perioperative complications and achieve better surgical results. However, the safety and effectiveness of intermediate approach have not been verified,in this prospective clinical study, the investigators will use a robotic surgical platform to perform robot-assisted pancreaticoduodenectomy surgery through the intermediate approach to verify its safety and efficacy.