Objective To investigate the advantages and efficacy of traction with titanium clips in endoscopic submucosal dissection(ESD)for large laterally spreading tumor(LST)in rectum and sigmoid colon.Methods 67 patients with large sigmoid or rectal LST underwent ESD from January 2018 to June 2022 were analyzed retrospectively,including 32 patients in Group A and 35 patients in Group B.Group A was treated with clip-line traction and group B was treated with traditional ESD.The size of lesion,the total operation time,the submucosal dissection time,submucosal dissection rate,submucosal injection number,en bloc resection rate,R0 resection rate,curative resection rate and complications of the two groups were compared.Results LST-G-M was the most common type and villous adenoma was the main pathology in both groups.There were no differences in en bloc resection rate,R0 resection rate and incidence of complications between the two groups.The average size of group A was(13.6±8.4)cm2,significantly larger than that in group B(9.3±4.7)cm2,the total operation time was(42.3±10.3)min in group A,significantly shorter than that in group B(47.9±10.1)min,submucosal dissection time was(30.7±8.2)min in group A,significantly shorter than that in group B(36.1±7.6)min,submucosal injection number was(2.7±1.1)times in group A,significantly less than that in group B(3.5±1.2)times,submucosal dissection rate was(0.4±0.2)cm2/min in group A,significantly faster than that in group B(0.2±0.1)cm2/min,the differences were statistically significant(P<0.05).Conclusion Compared with traditional ESD,clip-line traction can provide a better surgical field and more effective dissection for large LST in rectum and sigmoid colon.