Abstract: Objective To analyze the factors affecting the bowel preparation effect of polyethylene glycol electrolyte powder （PEG-ELP） combined with dimethicone in hospitalized patients. Methods Clinical data of bowel preparation of 200 hospitalized patients who underwent colonoscopy were retrospectively analyzed. The influencing factors of bowel cleaning effect were analyzed. Results Univariate analysis showed that hypertension,dyslipidemia,positive urine ketone body,and colonoscopy scheduled in the afternoon were influencing factors of the cleanliness of bowel preparation,respectively （all P < 0.05）. Multivariate regression analysis indicated that dyslipidemia（OR = 2.312,95%CI（1.245,4.293）,P = 0.008）,hypertension （OR = 2.270,95%CI（1.193,4.318）,P = 0.013）,and colonoscopy scheduled in the afternoon （OR = 2.377,95%CI（1.279,4.416）,P = 0.006） were the risk factors for low quality of bowel preparation,respectively. Conclusion For hospitalized patients receiving bowel preparation with PEG-ELP combined with dimethicone,hypertension,dyslipidemia and colonoscopy scheduled in the afternoon are the independent risk factors affecting bowel preparation before colonoscopy.