〔Abstract〕 Objective To study the diagnostic value of biopsy pathology in colorectal cancer. Methods A total of 100 patients with colorectal cancer admitted to the Second Affiliated Hospital University of South China from May 2022 to April 2023 were retrospectively selected. According to the operating norms of paraffin wax pathological examination before surgery, pathological biopsy samples of colon and rectum obtained by intestinal endoscope were carried out for pathological examination, and clear pathological diagnosis results were found after surgery. The results of preoperative and operative pathological diagnosis were compared. Results The pathological diagnosis of 100 patients with colorectal cancer showed that 70 patients with colon cancer and 30 patients with rectal cancer. Among the 70 cases of colon cancer, 35 cases of sigmoid, 13 cases of ascending colon, 12 cases of transverse colon, and 10 cases of descending colon were affected. The coincidence rate between preoperative pathological biopsy and surgical pathological diagnosis of 100 patients was 98.00 %, and there was no statistical significance between the two methods in the diagnosis of different types of colorectal cancer (P > 0.05). Different types of colorectal cancer (adenocarcinoma, mucinous adenocarcinoma, carcinoid) can show significant histological differences under pathological biopsy. Conclusion Preoperative pathological biopsy is consistent with surgical pathological diagnosis. Preoperative pathological biopsy can be used as the basis for diagnosis and treatment of colorectal cancer.