Objective To explore the molecular defects of CYP17A1 gene in a family with 17?-hydroxylase deficiency. Methods Clinical features and laboratory data were collected from the pedigree with 17?-hydroxylase derficiency and the proband was hospitalized in Shanghai Clinical Center for Endocrine and Metabolic Diseases. PCR and subclone sequencing were performed to screen the mutations of CYP17A1 gene. Results The patient was diagnosed as 17?-hydroxylase deficiency according to the clinical presentations, laboratory examination and blood level of steroid hormones. A new type of mutation was identified as a base deletion and a base transversion (TAC/AA) at codon 329 in the patient. It produced a missense mutation of Tyr→Lys at codon 329 and the open reading frame shift following this codon. The patient was homozygous mutation and her parents were heterozygote carrying TAC329AA mutation. Conclusion 17?-hydroxylase deficiency in this family was caused by CYP17A1 mutation (TAC329AA) which was first identified as a complex defects of missense mutation and the open reading frame shift at codon 329.