Abstract: Objective 21- hydroxylase deficiency accounts for the majority of congenital adrenal hyperplasia. Inadequate awareness of the disease by patients，family members and doctors often leads to delayed diagnosis and poor prognosis. Regular follow-up with precise hydro-cortisone replacement therapy can depress the production of adrenal derived sex hormones and avoid rapid growth of bone age，it enables patients to have normal puberty and fertility. Methods The author reported a female had this disease with treatment interruption for six years，combining with literature review to analyse the deficiencies in diagnosis and treatment. Results Due to the discontinued treatment，the degree of virilization was further increased，the final height was shortened，and the psychosocial orientation tended to male. Thus，early treatment is needed. Conclusion Lack of awareness of 21- hydroxylase deficiency and treatment delay are not uncommon. We need long- term follow- up and check for patients with congenital adrenal hyperplasia.

Key words: 21-hydroxylase deficiency, congenital adrenal hyperplasia, interruption of treatment, female virilization, case report