〔Abstract〕 Objective To compare the therapeutic effects of endoscopic mucosal resection (EMR) and endoscopic mucosal dissection (ESD) in the treatment of early colorectal cancer and precancerous lesions. Methods From January 2021 to June 2022, a total of 80 patients with early colorectal cancer and precancerous lesions admitted to Wuyishan City Hospital were selected as the study objects. They were divided into two groups by random drawing method, 40 patients in each group, and were respectively treated with EMR (EMR group) and ESD (ESD group). The effects of different treatment schemes were compared. Results The amount of intraoperative blood loss in the EMR group was lower than that in the ESD group, and the duration of operation and hospitalization were shorter than those in the ESD group. The curative resection rate and monolithic resection rate in the ESD group were higher than those in the EMR group, and the differences were statistically significant (P < 0.05). There was no significant difference in basal lesion residual rate between the two groups (P > 0.05). The levels of serum CD3⁺ , CD4⁺ and CD4⁺ /CD8⁺ in the ESD group were higher than those in the EMR group. The one-year recurrence rate and complication rate of the ESD group were lower than those of the EMR group, the differences were statistically significant (P < 0.05), and the one-year survival rate was not statistically significant between the two groups (P > 0.05). The positive rate of CEA associated cell adhesion molecule 1 (CEACAM-1) in the ESD group was lower than that in the EMR group, and the difference was statistically significant (P < 0.05). Conclusion For the treatment of early colorectal cancer and precancerous lesions, ESD lesion resection has high efficiency, which can help patients improve cellular immune function and help patients recover, but the operation and hospital stay are longer than EMR, and the best treatment plan can be selected according to the actual situation of patients.