The detection and timely management of early colorectal cancer is an effective means to improve the prognosis of colorectal cancer. Although there is a convergence of views on early-stage colorectal cancer in terms of incidence statistics, preoperative diagnosis, treatment plan selection and prognosis estimation, etc. It is believed that paying high attention to the following high-risk groups can help detect early colorectal cancer: 1. those who have gastrointestinal symptoms over 30 to 40 years old; 2. those who have a history of colorectal cancer; 3. those who have precancerous colorectal lesions such as adenoma, ulcerative colitis and schistosomiasis; 4. those who have a family history of cancer, a history of familial polyps and hereditary colon disease; 5. those who have a history of pelvic radiotherapy; 6. those who have a history of gallbladder or appendectomy. The main diagnostic methods for early colorectal cancer are barium enema X-ray and endoscopy. Histologically early colorectal cancer is divided into two types: intramucosal cancer (m cancer) and submucosal cancer (sm cancer). In order to choose the appropriate treatment, there is now a tendency to subdivide sm cancer. Because the depth of cancer infiltration into submucosa and the incidence of lymph node metastasis in sm cancer are different, the choice of treatment modality is different. The subdivision method is to divide the submucosal layer into 3 layers, from superficial to deep, sm1, sm2 and sm3, and it is now considered that m and sm1 cancers can be resected by endoscopy. The following examination methods can be used to determine the depth of cancer infiltration. X-ray diagnosis If the barium is well mucilaginous coated, the effect of barium enema X-ray is similar to that of endoscopy. when X-ray barium enema is used, the residue in the intestine should be minimized to improve the contrast effect. The barium concentration is generally 65% to 75%. This can make the intestine tiny and small superficial type of lesions show up. the lesion morphology in the X-ray photography are: 1. with a tip. For long tissues, endoscopic resection can be used, but if the tissues are thicker than 2cm, it may be sm cancer; 2. In addition, the depth of infiltration can be determined according to the fold pulling image and intestinal wall deformation. If there is concentration of mucosal folds, it indicates that the cancer infiltrates above sm2; most of the lesions without concentration of folds are m cancer or sm1 cancer. However, it is worth noting that 22% of sm2 and sm3 have no concentration of folds. The deformation of the intestinal wall at the base of the lesion was classified as angular, arcuate and plateau-like. Generally speaking, lesions with arc-shaped deformation of the intestinal wall suggest that most cancers have infiltrated above sm2. Angular deformation is often m or sm carcinoma. However, the angular deformation is often seen in tipped lesions due to the pulling of the lesion.