Yamada typing is a Japanese typing method for colon polyps, which is mainly based on the angle between the base of the polyp, the location of the bulge and the mucosa of the large intestine. There are four types of polyps, of which type 2 is a hemispherical polyp with an inconspicuous tip, an angle of less than 90 degrees between the polyp bulge and the mucosa, and a slightly reddish surface of the mucosa, which is sometimes indented. Yamada type 2 polyps are not likely to be malignant, most cases will not be cancerous, the prognosis is better, generally no more than 30%, but can not be completely excluded from the possibility of its development into malignant, the specific circumstances of the patient’s pathology tissue biopsy results to make a judgment. The degree of benignness or malignancy of GI polyps is mainly determined by pathological tissue biopsy, through surgery, pathological tissue biopsy of excised tissues, the report suggests that it is an adenoma or inflammatory hyperplastic polyp, then the patient belongs to benign lesions.