Objective：Alimentary tract hemorrhage is the most frequent complication after colonoscopic polypectomy. The aim of this study was to identify the risk factors for postpolypectomy bleeding（PPB）after endoscopic mucosal resection（EMR）. Methods：We retrospectively reviewed the clinical data of 111 patients who experienced PPB after EMR and 176 patients who did not. Results：Univariate logistic regression analysis showed that gender（male，P=0.008），numbers of polyps removed（≥3 polyps，P=0.001），polyp’ diameter（≥10 mm，P < 0.001），location（right colon，P=0.036），use of antithrombotic drug（P=0.015）were significantly correlated with PPB. Above factors，hypertension（P < 0.1）and pathological type（adenoma，P < 0.1）were analyzed by multivariate logistic regression，and only gender（male），polyps’ diameter（≥10 mm）and numbers of polyps removed（≥3 polyps）were significantly associated with PPB after EMR. Conclusion：Gender（male），polyps’ diameter（≥10 mm）and polyp number（≥3 polyps）are significantly associated with PPB after EMR，and we should pay more attention to these factors for preventing PPB