Objective To study the clinical manifestation of patients with congenital adrenal hyperplasia(CAH)and central precocious puberty(CPP).Methods Clinical data of120patients with21-hydroxylase deficiency was studied retrospectively.Among them,twenty patients with21-hydroxylase deficiency and CPP.These20patients were divided into2groups according to the treatment status and the relationship between the initial age of CPP presentation,bone age and steroid hormone replaced treatment was analyzed.Results The initial age of CPP presentation in group A was5.6±2.1years,the bone age was12.0±3.2years.The initial age of CPP in group B were6.8±1.1years,the bone age was11.7±2.0years.There were no statistical differences between the two groups.The CPP occurred at2.3years after treatment with hydrocortisone in group B.Conclusions Patients with congenital adrenal hyperplasia and CPP were closely related to the advanced bone age,earlier diagnosis and treatment could improve the prog-nosis.