Abstract: Rejuvenation is a key issue in the clonal propagation of trees and the application of biotechnologys to trees. Normally, juvenile trees have a strong rooting capability, vigor, straightup growth and high pest resistance, which highly underline the tree’s production. However, with development, the tree gradually loses these characteristics to enter a mature phase. Rejuvenation is a reverse process of the tree’s development to turn the mature phase into the juvenile phase. This paper describes research advances on juvenile character preservation in tissues or organs during tree development; potential juvenile competence in apical meristem; understanding the rejuvenation mechanism at the physiological, biochemical and molecular levels; and rejuvenation methods. Some questions in rejuvenation research are raised and further research emphases discussed.