Abstract: 【Objective】Clarify the effects of planting densities on the agronomic traits and yield of broad beans,to explore the optimal planting density of broad beans in the central and western regions of Inner Mongolia.【Methods】In 2022 and 2023,using Mengcan No. 1 and Mengcan No. 2 broad beans as experiment materials and randomized block design,five planting densities, D1（90 000 plants/hm²）,D2（120 000 plants/hm²）,D3（150 000 plants/hm²）,D4（180 000 plants/hm²）,and D5（210 000 plants/hm²） were set up to analyze the effects of different planting densities on the main agronomic traits,yield traits,yield and economic benefits of broad beans.【Results】The plant height of broad beans had increasing trend with the increase of planting densities,while the total number of branches and effective branch number per plant had decreasing trend. With the increase of planting densities,the main yield traits,yield and economic benefits of broad beans had the trends of first increase and then decrease. The performance of different planting densities were：D4>D3>D5>D2>D1. Under D4 treatment,the yield of Mengcan No. 1 and Mengcan No. 2 were highest at 2 089.74,2 210.66 kg/hm² in 2022 and 2 152.15,2 249.66 kg/hm² in 2023,the net income were highest as well at 13 439.76,14 478.16 yuan/hm² in 2022 and 13 947.97,14 739.54 yuan/hm² in 2023.【Conclusion】The optimal planting density for broad beans in the central and western regions of Inner Mongolia was 180 000 plants/hm². Under this density,the agronomic traits of broad bean performed well,the yield and economic benefits were the best.

Key words: Broad bean, Planting density, Agronomic traits, Yield, Economic benefits