The Intergovernmental Panel on Climate Change projects that atmospheric \[CO2\] will reach 550ppm by 2050. Elevation of \[CO2\] will invariably influence soybean growth and yield. Recently soybean response to elevated \[CO2\] have been mostly researched in chambers and enclosures. This is the first FACE(Free air CO2 enrichment) study of soybean in china，The CO2 regimes investigated were ambient ((389±40)μmol?mol-1) and FACE ((550±60)μmol?mol-1).This is the second such study in the world after American SoyFACE. Results showed that the weight of leaf, stem, pop and the above\|ground biomass increased with Elevation of \[CO2\], the mean above\|ground biomass of two varieties in FACE significantly increased by about 52.30% compared to these grown in ambient air at harvest. The leaf area of Zhonghuang35 increased with Elevation of \[CO2\], whereas leaf area of Zhonghuang13 decreased. The specific leaf weight of two soybean cultivars increased at the stage of filling pod in FACE, and significantly increased by 23.08% in Zhonghuang35. Plant node number, branch number, and stem diameter were increased in FACE, the stem diameter of cultivars Zhonghuang35 and Zhonghuang13 significantly increased by 7.18%,26.33% respectively at harvest. Because of the increase in pod number per plant and the mass of individual seeds, the average yield was increased by 30.93% in FACE. The average harvest index wasn′t significantly affected by elevated \[CO2\]. Proportion allocation of leaf, stem and pod biomass to above\|ground over the growing season was also not significant. The effect of FACE on soybean significantly varied between two soybean cultivars. Our main conclusion is consistent with the results of SoyFACE studies, such as the increase in yield and biomass and the decrease in harvest index with elevated \[CO2\], but with larger effects than those found in the SoyFACE studies.