Objective To systematically evaluate the effect of dietary intervention on blood glucose during intestinal preparation for colonoscopy. Methods Randomized controlled trials (RCTs) on the effects of different interventions on blood glucose during bowel preparation in colonoscopy patients were retrieved on PubMed, CNKI, and WanFang, and RevMan 5.3 software was applied for meta-analysis based on the intervention groups. Results A total of 10 RCTs in 8 papers, including 3 345 patients, 1 603 patients in the control group and 1 742 patients in the intervention group, were reviewed. Meta-analysis results showed that 10 studies reported incidence of hypoglycemia and interventions during intestinal preparation, and heterogeneity among researches was statistical (P<0.000 01, I2=80%). Under random effects model combined with effect quantity, compared with the control group, dietary intervention could significantly reduce the incidence of hypoglycemia during bowel preparation, the difference was significant (OR=0.19, 95%CI:0.09-0.40, P<0.05). Conclusion Dietary intervention during intestinal preparation for colonoscopy can prevent the occurrence of hypoglycemia and avoid relative adverse reactions and parasympathetic nerve activity. However, due to the limited number and quality of included researches, the above conclusion need to be verified by more high-quality RCTs.