【Abstract】Objective To investigate the diagnosis and treatment of primary small intestinal tumor (PSIT). MethodsEighty-eight cases of PSIT were analyzed in our hospital retrospectively. Results Thirty-six cases were diagnosed before operation, 52 cases were misdiagnosed and the percentage amounted to 59.1%. The major clinical manifestations of PSIT were abdominal pain (66 cases, 75.0%), obstruction (56 cases, 63.6%), abdominal mass (51 cases, 58.0%) and stool with blood (48 cases, 54.5%).The major pathological types of PSIT were adenocarcinoma (55.7%), sarcoma of smooth muscle (25.0%), lymphoma (13.6%), fatty sarcoma (5.7%). The tumors of 36 cases located in jejunum (40.9%), 34 cases in ileum (38.6%) and 18 cases in duodenum (20.5%).Conclusion It is difficult to diagnose PSIT before operation. The following advice could help to get a correct diagnosis: ① Surgeons should be alert when meeting a patient with the above symptoms, and then collect and analyze the clinical data comprehensively. ②Patients over 40 years with complaints of inexplicable abdominal pain, weight loss, anemia, dyspepsia and abdominal mass should be examined appropriately by gastrointestinal X-ray, gastrointestinal endoscopy, ultrasonography, CT and angiography of superior mesenteric artery. ③When the diagnosis can’t be confirmed, an exploratory operation should be performed immediately to avoid the delay of treatment. ④The treatment of PSIT includes radical resection of small intestine and chemotherapy according to the pathological results of tumor.