Phenylketonuria (PKU) is an autosomal recessive hereditary disease and a common disorder of amino acid metabolism. The average incidence of PKU in China is approximately 1/11 000. It is characterized by lower incidence in the South and higher incidence in the North, particularly the Northwest. PKU is a treatable disease and has been listed in the national newborn screening program. Neonates with positive indication of screening can achieve satisfactory therapeutic effect by timely control of phenylalanine intake after the definite diagnosis. This guideline aims to summarize the knowledge of medical genetics and key points of clinical management of PKU, so as to improve the diagnostic level and standardize newborn screening and clinical treatment of patients.