Widespread areas of crop production are presently at risk for damage from ambient atmospheric ozone (O₃) concentrations. The concentration of tropospheric O₃ has been rising due to aggravating urbanization since the Industrial Revolution, it has had a significant impact on plants and plants play an important role in adjusting structure and function of the ecosystem. Thus, to correctly evaluate how elevated O₃ concentration affects plants is of great significance. AsA-GSH cycle has an important function of eliminating H₂O₂, and the efficiency of AsA-GSH cycle in plants can be stimulated by moderate stress conditions to scavenge reactive oxygen species (ROS). In this research, open-top chambers (OTCs) were used to investigate the mechanism of AsA-GSH cycle to eliminate ROS and the effects on growth and development of plants under troposphere O₃ stress. The results showed that, compared with control, the O₃ concentration of (80±10) nL/L and (110±10) nL/L induced an increase on malondialdehyde (MDA) content, relative electrical conductivity and a decrease on superoxide anion (O ^{- ·} ₂) production rate, hydrogen peroxide (H₂O₂) content and the activities of superoxide dismutase (SOD) during the whole growth stage. Simultaneously, O₃ stress resulted in lower content of ascorbic acid (AsA) and glutathione (GSH), and higher content of dehydroascorbic acid (DHA) and oxidized glutathione (GSSG) of ASA-GSH cycle. It showed a trend of increasing in earlier stage and decreasing in later stage of the activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR) and glutathione reductase (GR), while the dehydroascorbate reductase (DHAR) activity was increased in earlier period, decreased in middle period and then increased in later period compared to control, respectively. The results indicated that elevated O₃ concentration accelerated ROS metabolism rates and peroxidation damage, reduced the efficiency of AsA-GSH cycle and antioxidant system could not tolerate O₃-induced injure, thus increasing membrane lipid peroxidation and resulting in a significant negative effect on soybean. Also, in the early of O₃ treatment, the intensity of stress was low; the protection of plants played an important role to increase the efficiency of removing ROS and reduce ROS damage by improving the efficiency of AsA-GSH cycle. With stress intensity increasing, the structure of antioxidant system in soybean leaves was damaged, resulting in rapid accumulation of ROS. And O₃ stress caused an acceleration of caducity that might be in part responsible for the reduction of antioxidant ability. This paper reveals the effects of different treatments on ROS metabolic parameters and the response of AsA-GSH cycle in soybean leaves under elevated O₃, which can analyze its ROS metabolic response mechanisms to elevated O₃ concentration and provide references for the response mechanism of plants, and how to prevent soybean from O₃ injury and predict the feasibility of soybean under future climate change.