Duplicated kidneys are a common congenital malformation of the urinary system, occurring in about 1 out of 1500 people. The main cause is the abnormal development of unilateral or bilateral renal structures during development, which results in the overlapping of two renal structures. Each kidney structure may have its own renal pelvis and ureter, which is called a duplicate kidney. Most patients can have no specific signs and symptoms, and it is only detected on imaging tests, such as ultrasound, but some patients can have recurrent urinary tract infections, urinary incontinence, and other symptoms, and this is when treatment is needed. The deformity is usually corrected by surgical treatment, usually the effect is good after surgical treatment, basically can restore normal function. This kind of duplicate kidney, unilateral, bilateral can be, usually unilateral than bilateral incidence is higher, may be about six times higher. Either way, early detection and treatment have a better prognosis.