Abstract: Objective To investigate the effect of endoscopic endoscopic submucosal dissection(EMR)and endoscopic submucosal dissection(ESD)in the treatment of colorectal cancer. Methods A total of 164 patients with colorectal cancer were selected and divided into control group and research group according to the random number table method. The control group received EMR, while the research group received ESD. The operation time, intraoperative blood loss and excision of lesions with different diameters of the two groups were compared. The levels of tumor markers such as cancer antigen 125(CA125), CA199 and carcinoembryonic antigen(CEA)in the two groups before and after treatment were detected and analyzed, and the incidence of postoperative complications was compared. Results The operative time of the study group was longer, and the intraoperative blood loss was more than that of the control group(P<0.05). The rates of complete resection of lesions with diameter< 2 cm in the control group and the research group were 80.00% and 86.11%, respectively, but there were no significant differences(P>0.05). The rate of complete resection of lesions with diameter ≥2 cm in the research group was 91.30%, which was significantly higher than 61.70% of the control group(P<0.05). There were no significant differences in the levels of CA125, CA199 and CEA between the two groups before treatment(P>0.05). After treatment, the levels of CA125, CA199 and CEA in the research group were lower than those in the control group(P<0.05). The incidence of complications in the study group was 18.29%, which was significantly higher than 7.32% in the control group(P<0.05). Conclusion EMR and ESD both have advantages in the treatment of colorectal cancer, and the corresponding surgical methods can be selected reasonably - according to the actual situations of patients.