Objective To explore the clinical application value of painless endoscopic cold resection in treatment of 5 ~ 9 mm flat sessile colorectal polyps in elderly patients.Methods 124 elderly patients with flat sessile colorectal polyps with a diameter of 5 ~ 9 mm found by painless enteroscopy were randomly divided into study group (n = 64) and control group (n = 60). The study group was treated with trap for cold resection of polyps, and the control group was treated with high frequency electric resection after submucosal injection to lift the polyps. The operation time, intraoperative bleeding, one-time complete resection rate, specimen recovery rate, polyp pathological type, postoperative complications and operation cost were compared between the two groups.Results The operation time in the study group was shorter than that in the control group, the operation cost was less than that in the control group, the postoperative abdominal distension was less than that in the control group, the difference were statistically significant (P < 0.05); There were no significant difference in intraoperative bleeding, one-time complete resection rate, specimen recovery rate, postoperative abdominal pain and bleeding between the two groups (P > 0.05).Conclusion Cold resection of 5~9 mm flat sessile colorectal polyps with a snare under painless endoscopy has the advantages of short operation time, high safety, few complications and low cost, and avoids the damage of high-frequency electricity to the surrounding normal mucosa.