Most of the pediatric congenital hydronephrosis is found in prenatal ultrasound, and the etiology of the disease is more varied, which may be pelvic ureteral junction obstruction, congenital megaureter, duplicated kidney duplicated ureter, etc., among which, pelvic ureteral junction obstruction (UPJO) is more common. It may also be caused by physiologic hydronephrosis, which is different from pathologic hydronephrosis in that physiologic hydronephrosis gradually decreases or disappears during postnatal observation, whereas the latter gradually worsens, with recurrent fever, urinary tract infection, and renal insufficiency. Clinical evaluation of hydronephrosis with pelvic-ureteral junction obstruction includes symptoms, physical examination, and ancillary tests. Symptomatic observations include fever, abdominal pain, abdominal mass, urine character, and presence of trauma. Physical examination includes abdominal mass size, renal region tenderness, etc. Adjunctive examinations include: abdominal plain film, ultrasound, intravenous urography, renal nuclear isotope catheterization (ECT), magnetic resonance imaging of the urinary tract (MRU), routine urinalysis, and urine bacterial culture. Additional urinary CT (CTU) examination is required if necessary. When the diagnosis is clearly UPJO, one is faced with surgical options. Current surgical options include open dissecting pyeloplasty, laparoscopic dissecting pyeloplasty, percutaneous nephrolithotomy with internal incision of the pyeloureteral junction, and balloon dilatation of the upper ureter. For those with heavy hydronephrosis and recurrent urinary tract infections, sometimes it is necessary to do nephrostomy to drain urine before surgery and further evaluate the change of renal function to determine whether the affected kidney can be preserved or percutaneous nephrostomy combined with anti-inflammatory treatment to make the urinary tract infections get better, and then choose nephronic deconstruction or renal pelvic plasty. Of all the surgical options for kidney preservation, dissecting pyeloplasty has the best results. Laparoscopic surgery has now been able to achieve similar efficacy of open surgery, and at the same time has the characteristics of minimally invasive, cosmetic, and rapid postoperative recovery, which is currently recommended. Robot-assisted laparoscopic dissecting pyeloplasty is commonly used abroad for the treatment of UPJO. After the implementation of any surgical treatment plan, close postoperative observation is required. Postoperative auxiliary examination evaluation mainly uses urine routine, ultrasound and so on. MR, ECT, etc. need to be reviewed when necessary. Recurrent urinary tract infections and restenosis of the pyeloureteral junction may occur in some pediatric patients after surgery, requiring further management, reoperation, and so on.