Design：Prospective randomized controlled study. Setting：Three tertiary referral hospitals. Patients：we will recruit a total of 330 polyps(3-9mm). Interventions:Enrolled patients were randomly assigned to one of the two polypectomy protocols (CSP vs. HSP) using a computer-generated random sequence. If a patient had one or more polyps, all eligible polyps were removed using the initially assigned polypectomy protocol. After the initial polypectomy, additional EMR was performed at the polypectomy site to assess the presence of residual polyp tissue.