Taking the soybean (Glycine max) cultivar Tiefeng 29 as test material, and by using open0top chamber, this paper studied the effects of elevated O₃ concentration and UVB radiation on the leaf chlorophyll content, lipid peroxidation, reactive oxygen species (ROS) production rate, antioxidation enzymes activities, and the grain yield. During the growth period of soybean, as compared with the control, the leaf Chl a, Chl b and Chl(a+b) contents under the stresses of O₃ and UV-B had a decreasing trend, the relative electrical conductivity, malondialdehyde  content, superoxide anion (O₂^-·) production rate, and hydrogen peroxide (H₂O₂) content increased, and the activities of superoxide dismutase, peroxidase  and catalase as well as the grain yield decreased. O₃+UV stress aggravated the leaf membrane lipid peroxidation, promoted the ROS production, and decreased the plant antioxidant capacity and leaf chlorophyll content. The negative effects of O₃ stress on soybean leaves were more close to the impacts of O₃+UV-stress, suggesting that O₃ might play an important role in the combined stress.