Cystic kidney disease is a group of diseases characterized by the presence of “cystic lesions” in the kidneys. With the improvement of prenatal diagnosis technology, these diseases are more frequently detected in the fetal period. The following diseases are common in the fetal period: 1. Polycystic kidney dysplasia This disease has no familial tendency, no gender difference, and is mostly unilateral. The kidney loses its normal shape and is replaced by multiple cyst-like structures of varying sizes, with the appearance of a pile of grapes, with thin and transparent cyst walls that are not interconnected. There is usually no normal kidney tissue, and the intercapsular tissue may contain foci of cartilage, and the glomerulus and tubules are in primary form. It is often accompanied by atresia or ectopic opening of the ureter on the affected side. About 5-10% of children with unilateral lesions may have contralateral hydronephrosis and about 15% may have vesicoureteral reflux on the opposite side. Children with bilateral lesions may have hypohydramnios or pulmonary dysplasia and may have a Potter face. Unilateral lesions can be nephrectomized, while bilateral lesions can lead to respiratory failure and death in the neonatal period. Medullary spongy kidney is common in males, with congenital developmental abnormalities, mostly bilateral, and usually without family history. The lesion is confined to the renal cone, and the papillae are dilated to form a cystic cavity of varying size, which resembles a sponge in cross-section and contains jelly-like clots and small stones. The disease is mostly asymptomatic. However, the disease can develop at any age and is mainly characterized by recurrent hematuria, urinary tract infections, and small intramedullary stones that can cause renal colic. Asymptomatic and uncomplicated patients do not need treatment, and symptomatic patients are treated symptomatically. 3.Autosomal recessive polycystic kidney This disease is autosomal recessive disease, the pathogenesis is unknown. Both kidneys are obviously enlarged, smooth in shape and honeycomb-shaped in cut surface. The disease cannot be cured and can only be treated symptomatically. If necessary, kidney transplantation can be performed. Severe cases often die in the neonatal period due to pulmonary dysplasia and respiratory failure.