The left subventricular cyst is mainly located in the ventricle, below the anterior horn of the lateral ventricle and the body of the ventricle, with small cyst-like changes called left subventricular cyst, which is usually seen in preterm infants and is related to the dysplasia of the embryonic developmental layer of preterm infants, and usually disappears gradually in 2-4 weeks after birth. If the cyst grows progressively and causes symptoms such as nausea, vomiting, poor appetite and headache, it is necessary to go to the neurosurgery department of the hospital for surgical treatment, such as craniotomy or Endoscopic cystostomy, etc.