Objective To investigate the common causes and clinical characteristics of infant colonoscopy, and to evaluate the safety, feasibility and clinical value of colonoscopy in infants. Methods Clinical data of 86 infants underwent colonoscopy from January 2011 to January 2021 were retrospectively analyzed. Results All infants, including 50 boys and 36 girls, with a median age of 7.0 (4.8-10.0) years, were grouped according to age, ≤6 months group (n=33 ) and 6-12 months (n=53). A total of 91 painless colonoscopies were performed, and 65 reached the ileocecal region (23 in the terminal ileum and 42 in the ileocecal region), with a success rate of 71.4%. The main clinical manifestations include hematochezia (36/86,41.8%), persistent/chronic diarrhea (18/86,20.9%), hematochezia and diarrhea (22/86,25.6%). The difference of the reason for colonoscopy examination was statistically significant between ≤6 months and 6-12 months groups (P<0.05), and the proportion of prolonged/chronic diarrhea was higher in the ≤6 months group. Of the 86 patients, 83 children received the etiological diagnosis after colonoscopy (96.4%), with food allergy-related gastrointestinal disorders (32/86, 37.2%), colonic polyps (19/86, 22.1%), colonic (rectal) inflammation (18/86, 20.9%), and VEO-IBD (6/86,7.0%). There were no serious complications such as respiratory arrest or sudden cardiac arrest during the procedure, two cases had complication after colonoscopy, one case of hemorrhage and the other of intestinal perforation. Conclusion The infant underwent colonoscopy have the different disease spectrum from older children, and colonoscopy plays an important role in the diagnosis of the chronic diarrhea and hematochezia in infant. The risk of infant colonoscopy operation is higher than that of older children, and the indications for colonoscopy should be strictly controlled.