Reasonable planting density and delayed nitrogen application are important for improving soybean yield. In order to demonstrate the responses of different soybean cultivars to planting density and nitrogen application period，this study used soybean cultivars Qihuang 34 and Zheng 1307 as experimental materials，and adopted a split plot design with soybean cultivars as main plots and planting density and nitrogen application period as subplots. The experiment was conducted at Xinxiang，Henan province in 2020. The differences in agronomic traits，biomass accumulation and production components were analyzed. The results showed that the yields of Qihuang 34 and Zheng 1307 were 4027.55-4748.20 and 4783.65-5113.60 kg/hm² in the density range of 180000-270000 plants/hm²，respectively. The yield of Zheng 1307 was 12.2%-21.8% higher than that of Qihuang 34. The yield of the two cultivars did not change significantly under different planting densities. With the increase of density，the stem diameter，branches，effective pod number，effective grain number and 100-grain weight decreased，but stem elongation，shoot and root biomass increased in Qihuang 34；the stem diameter and effective branching decreased，but biomass per hectare increased in Zheng 1307. The application period of nitrogen fertilizer had a significant effect on the yield of Qihuang 34，with the highest yield under pod-filling stage application，increased by 5%-8% and 8%-17% compared to the seedling and full bloom stages，respectively. For Zheng 1307，the yield was not significantly affected by the application period，but it was higher under pod-filling stage application than the other treatments when planted at 270000 plants/hm²，with the effective pod number and 100-grain weight responded to nitrogen application period significantly. In conclusion，soybean plants can maintain its population yield by adjusting agronomic characters and the dry matter accumulation in the shoot and root within the reasonable planting density range of 180000-270000 plants/hm². Delayed nitrogen application had a yield-increasing effect on Qihuang 34 but not Zheng 1307. These results can provide theoretical and scientific basis for stably increasing the soybean yield in the Huang-Huai-Hai region and implementing the “soybean revitalization” strategy.