Increased lymph nodes after rectal cancer surgery are usually caused by bacterial infection, wound not healed, lymph node metastasis and so on. 1. Bacterial infection: bacterial infection is usually caused by patients’ low immunity, etc. Usually there will be fever, cough, nausea and other symptoms, which will lead to lymph node increase after surgery. 2. Wound not healed: usually due to the patient’s not paying attention to the life and diet habits and other causes of wound not healed, resulting in increased lymph nodes in the postoperative period. 3. Lymph node metastasis: lymph node metastasis refers to the malignant tumor cells metastasizing in the lymphatic channel in the rest of the parts except the primary focus of the tumor, and usually there are symptoms such as fever, loss of appetite and increase of lymph nodes. It is suggested that rectal cancer patients should go to the hospital regularly for review after surgery, and please follow up when uncomfortable symptoms appear, so that early detection and early treatment can avoid delaying the condition.