Fetal posterior cranial fossa pool widening of 1.0 cm may be associated with hydrocephalus. Fetal posterior cranial fossa pool widening usually does not exceed 10 millimeters, and if it exceeds 15 millimeters it is more often considered to be due to hydrocephalus. It may be associated with excessive production of cerebrospinal fluid, chromosomal mutations or viral infections, and narrowing of the middle cerebral aqueduct. Hydrocephalus is a disease caused by the blockage of cerebrospinal fluid circulation due to the accumulation of too much cerebrospinal fluid within the ventricles of the brain or its inability to be absorbed. Typical symptoms include rapid increase in head circumference and head-to-face disproportion. Common therapeutic drugs for this disease are acetazolamide and mannitol. They are mainly used to inhibit the secretion of cerebrospinal fluid and relieve the symptoms of hydrocephalus. Surgical treatment modalities include shunt surgery and neuroendoscopic fistula surgery. If the widening of fetal posterior cranial fossa pool is found, it should seek medical treatment in time and under doctor’s guidance. Pay attention to rest on weekdays and avoid excessive exercise.