Abstract: 【Objective】 To clarify the differences of responses in flower and pod formation and yield to density between branching-type and single stem-type spring soybean varieties, 【Methods】 4 planting densities of 420,000 plants/hm² (D₁), 320,000 plants/hm² (D₂), 270,000 plants/hm² (D₃), and 220,000 plants/hm² (D₄) were applied for Suinong 52, a branch-type variety, and Xindadou 27, a single-stem variety, in a field experiment in 2020. 【Results】 The results showed that the number of flowers per plant of Suinong 52 and Xindadou 27 decreased by 42.04% and 18.81%, respectively, at D₁ when compared with D₄, among which the number of main stem and branches decreased by 9.78% and 80.59% for Suinong 52.The decreases of flowers number in Suinong 52 were mainly found in the middle and upper parts of the main stem as well as in the first and second basal branches, whereas Xindadou 27 mainly reduced the flowers number in the middle and lower parts of the plant.In addition, the flowering period of Xindadou 27 ended early.Compared with D₄, the total number of flowers per unit area at D₁ increased by 6.60% for Suinong 52 (among which, the number increased by 65.94% in the main stem and decreased by 64.30% in branches) and 55.89% for Xindadou 27.The pod cavity number of single plant at D₁ decreased by 44.87% and 35.27% for Suinong 52 (decreased respectively by 17.90% and 74.82% in the main stem and branch) and Xindadou 27, respectively, when compared with D₄.The total number of pod cavity per unit area of Suinong 52 increased by 6.47% at D₃ compared with D₄ (among which, the number of main stem increased by 14.11% and decreased by 2.0% for branches), and Xindadou 27 increased the number by 24.32% at D₁ compared with D₄.The yield of Suinong 52 was found highest at D₂ (5,931.90 kg/hm², among which branches accounted for 19.96%), while D₁ was the highest one for Xindadou 27 (6,469.23 kg/hm²). 【Conclusion】 Higher total number of flowers, pod cavity and seed per unit area are the reasons for increasing yield under higher planting density.However, increasing the density seriously inhibits the formation of branched flowers, pods and seeds for Suinong 52, which leads to the increase in the total number of flowers, pod cavity and seed and yield smaller than that of Xindadou 27.The high-yield density of Suinong 52 (270,000~320,000 plants/hm²) is lower than that of Xindadou 27 (320,000~420,000 plants/hm²).