To comprehensively retrieve the evidence on bowel preparation before colonoscopy in children, evaluate and summarize the best evidence, so as to provide scientific reference for clinical improvement of bowel preparation quality in children, as well as for children and parents.

According to the "6S" pyramid classification model of evidence-based retrieval resources, we systematically searched BMJ Best Practice, UpToDate, clinical guideline website, professional society website and database for clinical decisions, guidelines, expert consensus, evidence summary and systematicreview on children's bowel preparation before colonoscopy.The retrieval time limit was from the establishment of the database (station) to December 31, 2021.Two researchers independently evaluated the article quality, extracted theevidence and determined the level of evidence recommendation.

A total of 11 articles were included, involving 3 clinical guidelines, 4 systematic reviews and 4 expert consensus.After summarizing the relevant evidence, a total of 16 pieces of evidence were summarized from 8 aspects, including the method of education, diet preparation, the selection and use of intestinal cleanser.

The endoscopic team, surgeon, nurseand other multi-disciplinary teams should consider different ages and special conditions of children before colonoscopy, and jointly discuss the best bowel preparation plan, so as to improve the quality of children's colonoscopy.

Child; Colonoscopy; Bowel preparation; Best evidence; Evidence-based nursing