Abstract: The secondary growth is a significant biological activity for plant development, and the secondary xylem (i.e. wood) plays an important role for human life. The secondary growth includes several consecutive processes such as vascular tissue differentiation, secondary cell wall deposition, lignification, PCD and heart wood formation. Considerable evidence indicated that auxin is the major signal involved in several aspects of the ontogeny of the vascular system. At the same time, a suite of putative transcription factors such as MYB, NAC, AP2/EREBP, homeobox and MADS have been implicated in the regulation of the secondary growth. The candidate genes in the signaling and transcriptional regulation which have been identified will assist future investigations to unravel the molecular mechanisms of secondary growth. The important aspect in secondary growth and the identification of regulatory genes were reviewed here.