To compare the incidence of hypoglycemia between day-before bowel preparation and split-dose bowel preparation in colonoscopy patients. The effects of enterald ietary nutrients on the prevention of hypoglycemia and the preparation quality of the intestine during colonoscopy were compared. The patients who underwent colonoscopy were divided into the day-before bowel preparation group, the split-dose bowel preparation group, and the split-dose bowel preparation + enteral nutrient diet group. All patients had their finger blood sugar tested before colonoscopy. The peripheral blood glucose level was measured before operation. After the endoscopic examination, the intestinal cleanliness of the patients was evaluated through the Boston intestinal preparation scale by endoscopists. The incidence of day-before bowel preparation group and split-dose bowel preparation group and enteral nutrient intervention group were 14.38%(23/160), 17.50% (28/160)and 6.45% (4/62), respectively. The proportions of high quality intestinal cleaning were 31.25% (50/160), 35.00% (56/160) and 82.26% (51/62) in the three groups respectively. The incidence of hypoglycemia was higher in split-dose bowel preparation group than that in day-before bowel preparation group. Enteral nutrient intervention can effectively reduce the incidence of hypoglycemia and improve the quality of intestinal preparation, which is a recommended intestinal preparation method.