Great value in the early identification and treatment of adenomatous polyps or early canceration using colonoscopy has been recognized. A clear colonoscopic vision brought by good intestinal preparation will become crucial. Several studies have completed using the low-residue diet (LRD) versus a clear liquid diet (CLD) the day before colonoscopy that presenting contradictory results. Therefore, a more comprehensive and updated meta-analysis is needed to summarize the findings on the effects of LRD and CLD on intestinal preparation and the quality of coloscopy.The comprehensive search was performed in PubMed/MEDLINE, Scopus, Cochrane databases (February 2020). LRD vs CLD before colonoscopy were included in this study. Mantel-Haenszel or DerSimonian and Laird models with the relative risk (RR) to evaluate differences in intestinal preparation, tolerance, readiness to repeat preparation, detected of a polyp, and overall adverse reactions.Total 16 studies (N = 3413) were eligible. Patients with LRD compared with CLD indicated significantly better of tolerability (RR 0.92;95% CI,0.85-0.99; P < .05) and willingness to repeat intestinal preparation (RR 0.86; 95% CI 0.79-0.93; P < .05), but no differences with adequate intestinal preparations, detected polyp or overall adverse reactions (all P > .05).Patients with LRD the day before colonoscopy show better tolerance and willingness to repeat intestinal preparation, and no difference with adequate intestinal preparations compared with CLD, but the recommended level of evidence is weak. However, in terms of the detection rate of intestinal adenomas, the LRD group is not weaker than the CLD group, for its evidence level is high, and can significantly reduce the hunger experience of patients.