Congenital mental retardation is related to heredity, perinatal harmful factors, advanced maternal age and other causes. 1. Heredity: It mainly includes chromosomal abnormalities, genetic abnormalities and congenital craniocerebral malformations. Among them, chromosomal abnormalities are reflected in abnormal chromosome number, chromosome inversion or deletion. Congenital craniocerebral malformations are mainly manifested as familial microcephaly and congenital hydrocephalus. 2. Perinatal harmful factors: If pregnant women are exposed to radiation, electromagnetic wave or ingest contaminated food during pregnancy, it is easy to cause congenital mental retardation. Some congenital mental retardation is also related to maternal infection by viruses, bacteria and other pathogens during pregnancy, improper use of medication, smoking and drinking during pregnancy. 3. Older mothers: The chances of congenital mental retardation in older mothers are usually higher than in other mothers of the right age. As congenital mental retardation will affect the patient’s quality of life, health and so on. Therefore, after the diagnosis of the disease, rehabilitation training, psychotherapy and medication should be actively carried out, and regular medical review should also be conducted.