Objective To analyze the relationship between mental health of parents and therapy compliance for children with phenylketonuria(PKU) in Xi'an. Methods During January 2013 to August 2015,50 parents of PKU children were assessed with Symptom Checklist 90.They were diagnosed and treated in our hospital.Under the investigation on mental health of parents with PKU children,the factor scores were divided into group Ⅰ and Ⅱ.The normal people whose children were checked in child healthcare department were taken as control. Results The mental health levels of parents with PKU children were significantly lower than those of control group(P＜0.01).The mental health levels of parents with PKU children in groupⅡwere significantly lower than those of groupⅠ (P＜0.01).groupⅡ showed a good treatment compliance(χ²=9.717,P＜0.01).Logistic regession analysis suggested that family income was risk factor of mental health of parents.Family income and educational levels were important factors of children's treatment compliance. Conclusion It is very necessary that throughing health education to psychological counseling for parents of PKU children,in order to alleviate the parents psychological pressure and improve the compliance for children.