Abstract: Significat evidence indicates that the involvement of reactive oxygen species(ROS) in the ethylene biosynthesis is a general process,and superoxide radical as a kind of ROS participates mainly in the ethylene biosynthesis.The recent study focuses on the effect of ROS on the key enzymes for ethylene biosynthesis,ACC synthase and ACC oxidase,concerning their activities,kinetics characteristics,protein structure,and their gene expression.ROS is firstly induced in normal growing process or under stress and then activities or genes expression of the two enzymes are regulated by the reactive oxygen species,which may result in the change in ethylene biosynthesis.The current advance in the role of ROS in ethylene biosynthesis in plants is reviewed in this paper.The dual role of ROS in ethylene biosynthesis is also discussed.