Colon cancer with blood in stool is divided into two cases: 1. Bleeding in stool before operation suggests that the surface of tumor breaks down, or the tumor invades normal tissue blood vessels. Treatment is decided according to the bleeding amount. If the bleeding amount is very small, just black stool, or a small amount of blood dripping after stool, firstly, use hemostatic drugs to stop bleeding and hemocoagulase drugs to treat it. If the bleeding is relatively large, emergency surgery is needed. Emergency surgery is further divided into tumor-targeted surgery, i.e., resection of the tumor, including ligation and suture of blood vessels in the invaded section of the tumor. Through interventional means of treatment, interventional catheter is inserted to find the bleeding vessels for plugging and hemostasis; 2. Bleeding after colon cancer surgery, the most basic enteroscopy should be carried out to make clear the bleeding site, if it is bleeding from the original surgical anastomosis, it needs to be operated again, and if it is a new-onset lesion, such as bleeding from polyps and ulcers, it will be treated with local treatment.