Rising concentrations of near surface ozone (O₃) has become a major pollutant in many areas of China. As a strong oxidizer, O₃ has been proved to have many negative effects on photosynthetic physiology and carbohydrate accumulation of plants. Meanwhile, the increase of nitrogen deposition (N) is also an environment factor with negative effects on plant growth. N deposition means the process by which N compounds in the atmosphere enter an ecosystem through abiotic ways. China has become one of the countries with the most serious N deposition in the world. Nonstructural carbohydrates (NSCs), composed of soluble sugar and starch, are known as important energy substance in plants and play an indispensable role in energy transport, respiration substrate and osmotic regulation. The difference in the amount of NSCs in different organs can reveal the distribution of photosynthates. The contents and proportions of NSCs can also directly reflect the nutrient supply situation under different situations. Furthermore, the dynamic change of NSCs is also able to reflect the response of plants to the temporal and spatial variation of the environment. Soybean (Glycine Max (Linn.) Merr.) is an important food crop over the world. Many studies have been carried out on the effects of individual N deposition or O₃ concentration increase on soybean yield but there are few studies focusing on their combined effects on soybean biomass, especially the accumulation and allocation of NSCs. It is still not clear whether there is an interaction between the O₃ and N deposition. In this paper, elevated O₃ concentration and N deposition were selected as the main research object. To explore the effects of elevated O₃ concentration and N deposition on gas exchange, biomass as well as nonstructural carbohydrate (NSCs) accumulation and allocation in soybean, this study uses Open top chamber (OTC), setting two O₃ concentrations of O₃ (AA, normal atmosphere; AAO60. Normal atmosphere +60μg/m³ O₃) and two N application gradients (control; N addition) to carry out relevant experiments. A total of 6 Chambers were used with 3 as the control group and 3 as the O₃ treatment group. 5 repetitions were set for the control and treatment groups of N treatment in each chamber. The results show that:(1) The net photosynthetic rate (Pn) and stomatal conductance (Gs) of leaves were significantly increased by 96.21% and 83.77% after N deposition, but the positive effects of N deposition on biomass of soybean organs were not significant. The allocation ratio of soluble sugar and NSCs in roots decreased by 42.17% and 38.95%. The starch allocation ratio in leaves increased by 41.55% and the soluble sugar content of soybean and stem was increased by 59.41% and 95.29% after N deposition treatment, respectively. (2) After O₃ concentration treatment, leaf Gs increased by 94.89% and Pn decreased by 2.34%. The biomass of leaves, stems, roots and beans was significantly decreased by 38.14%, 56.25%, 66.67% and 25.49%, respectively after O₃ concentration treatment. The soluble sugar, starch and total NSCs in beans were significantly decreased by 21.94%, 49.65% and 30.55%, respectively. After O₃ concentration increased, the proportion of total starch in root system increased by 56.21%. (3) The combined treatment of O₃ and N deposition showed significant interactions on leaf net photosynthetic rate, transpiration rate, and NSCs components in beans, stems and roots, mainly presenting to be antagonistic. In summary, N deposition increased leaf photosynthesis and NSCs allocated to overground parts, but NSCs distributed to underground roots was decreased. Increasing O₃ concentration inhibited soybean growth and NSCs accumulation but increased the proportion of starch in root system. Significant interactions between two factors were observed as the N deposition can alleviate the damage caused by O₃ to photosynthesis and NSCs to a certain extent, but no similar effect on biomass decline was detected. This study helps understand the effects of N deposition, O₃ and their combined effects on the NSCs of soybean crops. This also helps to understand the internal mechanism of impacts, to scientifically assess the impact of climate change on crop quality and yield, and to provide data support for future decisions.