Prostate cancer generally relapses into castration resistant prostate cancer (CRPC) after androgen deprivation therapy, which may be associated with androgen metabolism, particularly de novo androgen synthesis apart from the amplification and mutation of androgen receptor and the activation of its signaling pathways. This article focuses on the advances in the studies of the changes in androgen metabolism and de novo androgen synthesis in CRPC as well as their possible mechanisms and clinical significance.