Abstract: Objective To investigate the effect of iodophor on wiping lens and transparent cap in endoscopic mucosal dissection(ESD). Methods A total of 484 patients with early gastrointestinal cancer and precancerous lesions by ESD treatment were selected and divided into routine group and iodophor group, with 242 cases in each group. The preparation before operation and method of removing focus during operation were the same in both groups. In the iodophor group, the lens and transparent cap were wiped with the medical cotton swab soaked in iodophor before and after the operation, and were wiped with the medical cotton swab soaked in the 0.9% sodium chloride solution in the routine group. The time of operation, the time of removing the focus, ratio of removal and wiping of the mirror two times and above and the incidence of ESD complications were compared between the two groups. Results All the patients were successfully removed at one time, and the success rate of operation was 100%. The time of ESD operation and time of removing focus in iodophor group were significantly shorter than those in routine group(P<0.05). The ratio of frequency of withdrawing mirror and wiping or equalling to and greater than 2 times in iodophor group was significantly lower than that in routine group(P<0.05). There were no significant differences in the incidence rates of bleeding, perforation and infection between the two groups(P>0.05). Conclusion The application of iodophor disinfectant in wiping lens and transparent cap before and during ESD operation can effectively reduce the frequency of withdrawing and wiping mirror, shorten the time of removing focus and time of ESD operation, which is an effective method to ensure clear vision in ESD operation.