Duodenal tumor is a kind of small bowel tumor, which refers to benign and malignant tumors occurring in the duodenum, with malignant being more common. Among benign duodenal tumors, adenoma is the most common, while among malignant tumors, adenocarcinoma is the most common. When duodenal tumor is suspected, duodenoscopy should be preferred to directly understand the location, size and morphology of the lesion. The treatment of duodenal tumor is based on surgical resection, which should be decided according to the nature, growth and location of the tumor. There are several procedures as follows: transendoscopic resection for benign tumors with tips; partial duodenal resection for small benign tumors that are far from the duodenal papilla and do not invade the pancreas and surrounding tissues; pancreatic head duodenectomy for tumors around the duodenal papilla or invading the pancreatic head, and pancreatic duodenectomy for most malignant duodenal tumors. In the postoperative period, chemotherapy and other treatments can be chosen according to the staging. If the tumor is locally fixed and cannot be resected, short-circuit surgery can be done to relieve or prevent obstruction; advanced malignant tumors cannot be resected and can be diverted. It is generally believed that the higher the location of small intestine tumor, the worse the prognosis. Adenocarcinoma has the worst prognosis, followed by malignant lymphoma and sarcoma. Early diagnosis of duodenal malignant tumor is difficult, so if there is discomfort, timely medical treatment is needed.