Rectal cancer is one of the common malignant tumors in the gastrointestinal tract, which seriously endangers human health. Early detection and treatment can greatly improve the survival rate of patients. The survival time of rectal cancer is related to many factors. In the early stage, the tumor is relatively limited and no distant metastasis has occurred, so the five-year survival rate of some patients can reach 60%-70% through regular surgical resection and regular review, especially the five-year survival rate of patients with stage I and II rectal cancer can reach 80%-90%. Patients with extensive systemic metastasis in late stage, such as lung metastasis and bone metastasis, cannot be surgically resected, so the survival rate is very low, and only systemic chemotherapy and targeted therapy can be used to inhibit the growth of tumor. If there is pain and bleeding obstruction caused by metastatic site, corresponding palliative treatment measures, such as radiotherapy, painkillers, fistula, etc., can be used. Therefore, when clinical symptoms appear, it is necessary to go to regular hospital for colonoscopy in time, early detection and early treatment can greatly prolong the life of patients.