Rectal cancer is a malignant tumor, and all malignant tumors have the possibility of recurrence and metastasis after treatment. Clinically, the recurrence rate of rectal cancer is expressed by 5-year survival rate. The time of possible recurrence and metastasis of rectal cancer after treatment is related to tumor stage and pathological staging, and the prognosis of rectal cancer patients after surgery is also related to pathological staging.Stage I rectal cancer patients can basically be cured after surgical radical resection, and the chances of recurrence are very small; Stage II rectal cancer, after regular standard treatment, has a 5-year survival rate of about 70-80%; Stage III rectal cancer, after regular standard treatment, has a 5-year survival rate of about 60-70%; and Stage III rectal cancer, after regular standard treatment, has a 5-year survival rate of about 60%-70%. Stage III rectal cancer, after regular standard treatment, the 5-year survival rate is about 60%-70%; Stage IV rectal cancer, after regular standard treatment, the 5-year survival rate is about 20%-30%. Pathologic classification of low-differentiated carcinoma has the highest degree of malignancy, and compared with patients with highly-differentiated carcinoma, the time of recurrence and metastasis is shorter, and the disease-free survival period is shorter. Therefore, if diagnosed with rectal cancer, comprehensive examination should be conducted as soon as possible to evaluate the condition and regular treatment. Through comprehensive treatment methods such as surgery, radiotherapy and chemotherapy, tumor development can be controlled and the possibility of recurrence and metastasis can be reduced after surgery. 1-3 years after surgery is the high incidence period of recurrent metastasis for rectal cancer patients, 80% of recurrent metastasis occurs within 3 years after surgery, 95% of recurrent metastasis occurs within 5 years after surgery. Postoperative should follow the standard review program every 3-6 months, if recurrent metastasis is found, timely treatment.