The effects of continuous returning of corn straw and nitrogen application level on dry matter，nitrogen accumulation and distribution and yield of soybean under maize-soybean rotation system were investigated to provide theoretical basis for nitrogen nutrient management of soybean in black soil area.In this study，Heihe 43 was used as the test soybean variety，and a conventional fertilization(N 49.2 kg/hm²，N2-)treatment was set up in the experimental area without straw returning.In the high-fertilizer test area(G，organic matter content≥45 g/kg)and the low-fertilizer test area(D，organic matter content <45 g/kg)，no fertilizer treatment(CK)，no nitrogen fertilizer treatment(N 0 kg/hm²，N0)，conventional nitrogen reduction 30% treatment(N 34.4 kg/hm²，N1)，conventional nitrogen application treatment(N 49.2 kg/hm²，N2)，and conventional nitrogen increase 20% treatment(N 59.0 kg/hm²，N3)were set up under the condition of straw returning.The changes of nitrogen accumulation and distribution in roots，stems，leaves，pods and grains，biomass and yield of soybean at different growth stages were analyzed.The results showed that compared with no straw returning，straw returning significantly increased soybean yield，dry matter mass and nitrogen accumulation by 15.1%-26.0%，44.1%-287.4% and 15.6%-54.4%，respectively. After 6-7 years of straw returning，the yield，dry matter mass and nitrogen accumulation of soybean in 2 years and 2 fertilizer areas were the highest in the treatment of N 34.4 kg/hm²(N1). Compared with the treatment of N 49.2 kg/hm²(N2)，the increase rates were 0.4%-2.1%，0.9%-24.0% and 10.3%-20.7%，respectively.In 2022，compared with the treatment of N 49.2 kg/hm²(N2)，the yield，dry matter accumulation and nitrogen accumulation of soybean treated with N 59.0 kg/hm²(N3)showed a decreasing trend，and the degree of reduction was more significant in high fertilizer area.In summary，the continuous returning of corn straw to the field under the maize-soybean rotation system could significantly increase the nitrogen absorption and accumulation and yield of soybean. The conventional nitrogen reduction of 30%(N 34.4 kg/hm²，N1)under straw returning was the suitable rate of nitrogen fertilizer for soybean in black soil area.