Abstract: Polyploid rootstocks have some specific and excellent traits such as dwarf，drought tolerance，salt tolerance and iron-deficiency tolerance. As being used as rootstock，polyploid could induce plants dwarf and enhance tolerance of trees to abiotic stress，such as drought，iron-deficiency，salt，heavy metal and chill. In citrus，cherry and apple，some polyploid rootstocks have been applied in production. Nonetheless，low fertility and genetic instability limit reproduction of polyploid rootstock. Although vegetative propagation，apomixes and sexual reproduction have been employed，polyploid rootstocks all have their own disadvantages，need improvements. Formation mechanisms of some specific traits of polyploid rootstocks have been researched，and these traits were concerned with their anatomical structure，expression of some stress resistance-related genes and metabolites. Abscisic acid（ABA）may take part in plant dwarfing regulation and plays an important role in drought tolerance of polyploid rootstock. In an overall view，application and researches of polyploid rootstock are both at the starting stage. In the subsequent processes，more new polyploid rootstocks should be bred，popularization and application should be speeded up，researches on reproduction methods and specific traits formation mechanisms should be reinforced.

Key words: fruit tree, polyploid rootstock, dwarfing, stress tolerance