Many patients remember to review their abdominal CT after ureteral cancer of the renal pelvis, but many forget to review their cystoscopy. There was a patient recently. He had radical pelvic cancer a year and a half ago and had regular postoperative CT examinations of the upper and lower abdomen, which never revealed any recurrence or metastasis. Recently, he started to have hematuria and discovered that seven or eight tumors had grown in the bladder. The tumors were superficial and did not metastasize, so he was discharged through surgery. Our study found that patients with ureteral carcinoma of the renal pelvis have a 30% chance of bladder tumor recurrence after surgery. Especially, patients in the middle and early stage can survive for a long time, and the chance of bladder tumor recurrence is greater. Once it is not detected in time, the tumor may infiltrate and metastasize, leading to serious and life-threatening consequences. Therefore, cystoscopy is very important. Although it is more troublesome, it can protect our health.