Objective：To investigate the clinical features and the diagnostic methods of primary small intestinal disease. Methods：The clinical data of 155 patients with primary small intestinal diseases diagnosed by pathological examination were collected for this retro－spective study. All patients were admitted to the First Affiliated Hospital of Chongqing Medical University from January 2011 to December 2015. Each patient’s complete clinical data including etiology，pathological diagnosis，predilection site，main clinical symptoms，supplementary examination and final diagnosis were analyzed in the study. Results：The common cause of primary small intestinal disease was the tumor，accounting for 68.39% of all cases，and most of them were malignant tumor. Small intestinal diver－ticulum，Crohn’s disease，and intestinal tuberculosis accounted for 18.29%，5.14%，3.87%，respectively. Other rare causes were acute hemorrhagic necrotizing enteritis，intestinal polyps and erosive enteritis. The proportion of primary small intestinal disease in male and female was 52.90% and 47.02%，respectively. The average age was （56.94±16.48） years. There was no significant difference in gen－der，age and etiology（P<0.05）；the chi-square values were 0.027，4.230 respectively. Abdominal pain was the most common symptom accompanied by gastrointestinal bleeding，weight loss，nausea，vomiting，abdominal mass and fever，accounting for 61.94%，38.06%，26.45%，21.94%，17.42%，12.90%，respectively. There was no significant difference in age and symptom（P<0.05）；the chi-square value was 8.020. The positive diagnostic rates of capsule endoscopy，abdominal CT and small intestinal enteroscopy were 72.73%，66.91% and 62.50% respectively. The positive diagnostic rates of abdominal CT combined with capsule endoscopy or small intestinal enteroscopy were 90% and 83.33% respectively. Conclusion：The clinical manifestations of primary small bowel diseases are lack of specificity，and small bowel tumor was the main cause of primary small intestinal diseases.Small intestinal disease should be highly suspected in patients with abdominal pain and gastrointestinal hemorrhage. Combined abdominal CT and endoscopic examination may improve the diagnosis rate of primary small intestinal diseases.