Phenylketonuria is an autosomal recessive genetic disease, which is characterized by backward intellectual development, light skin and hair pigmentation and foul-smelling rat urine. If children with phenylketonuria can be diagnosed and treated early, the prognosis is relatively good, and they can achieve the same level of physical and intellectual development as normal people. China’s newborn screening has been very popular, timely heel blood screening after birth, if the screening of children with problems, timely treatment and intervention, to avoid the occurrence of intelligence and mental retardation, as well as intellectual disability, can be the same as normal children grow up healthily. If timely intervention is provided, the child may grow up to have yellow hair, white skin, mental retardation, psychiatric symptoms such as epilepsy, increased muscle tone, and finally, an inability to take care of him/herself.