Urinary incontinence after rectal cancer surgery may be due to muscle injury, urethra infection, tumor proliferation and so on. 1. Muscle injury: when undergoing rectal cancer surgery, improper operation during surgery causes injury to pelvic floor muscle or urethral block muscle, which will lead to inability to control urine and true urinary incontinence. 2. Urinary tract infection: urinary tract infection after rectal cancer surgery will lead to acute edema and congestion of urethral mucosa, accompanied by increased sensitivity, resulting in urinary incontinence, but in this case, patients usually have the consciousness of urinating on their own. 3. Tumor proliferation: when the malignant tumor of rectal cancer patients spreads to the bladder, it will cause urinary incontinence. Some patients also have symptoms such as pain during urination and blood in urine. Rectal cancer patients who have discomfort after surgery should be examined and treated in time to clarify the cause of disease.