With the development of prenatal diagnosis and the popularity of ultrasonography, many newborns with hydronephrosis can be diagnosed after birth in combination with prenatal examination. Most newborns with mild to moderate hydronephrosis do not require surgical treatment and can improve on their own. Obstruction of the ureteropelvic junction is the main cause of hydronephrosis in infants and children, with predominant onset in boys and on the left side. Most severe hydronephrosis has organic obstruction, resulting in poor pelvic urinary drainage into the ureter and impaired pelvic emptying. When the increasing peristaltic force of the smooth muscle of the renal pelvis cannot overcome the obstruction, it leads to atrophy of the affected kidney parenchyma, dilatation of the collecting system, and impaired function of the affected kidney. If the hydronephrosis worsens, it may lead to progressive impairment of the affected kidney or compensatory hypertrophy of the contralateral kidney. The American Board of Neonatology-Perinatology in 2010 defined the following 6 criteria for early surgery: 1) anterior-posterior diameter of the renal pelvis greater than 3 cm; 2) anterior-posterior diameter of the renal pelvis greater than 2 cm combined with dilatation of the renal calyces; 3) fractional renal function less than 30%; 4) deteriorating renal function; 5) worsening hydronephrosis; 6) symptomatic hydronephrosis. The specific surgical procedure should be decided according to the age of the child, the degree of hydronephrosis, the general condition and the experience of the doctor and the hospital equipment. The worst case is that the kidney on the affected side is found to be non-functional and needs to be removed during the intraoperative investigation, but this is very rare. As long as the contralateral kidney is normal, the child’s growth and development are generally unaffected. Traditional open surgical incisions are usually 5-8 cm long, with significant tissue damage, slow postoperative recovery, and significant incisional scarring. The development of laparoscopic pyeloplasty requires special equipment, as well as a small operating space in the child’s abdominal cavity, requiring the operator to have skilled microscopic techniques and surgical experience, but the procedure is less invasive, has a faster recovery, and has good cosmetic results.