A pharmaceutical composition of a CYP17 inhibitor and a preparation method therefor. The composition comprises 17-(3-pyridyl)androstane-5, 16-diene-3b-alcohol or a derivative thereof, and an absorption enhancer, such as N-(8-(2-hydroxyl benzoyl)amino) caprylate (NAC). The composition has improved bioavailability, and can alleviate individual differences of patients to which drugs are delivered.