Abstract: 【Objective】 To investigate the effects of Bromus japonicus density on the physiological indicators and yield traits of wheat in the hope of providng a scientific foundation for identifying control metrics for Bromus japonicus in wheat fields and developing integrated management strategies. 【Methods】 The effects of different densities of B. japonicus (0, 50, 100, 150 plants/m²) on wheat physiological indicators and yield traits were studied and various models were used to fit the functional relationship between different densities of B. japonicusand wheat yield loss rate, and the optimal model was selected. Furthermore, the economic threshold for the control of B. japonicus was analyzed based on the economic injury level. 【Results】 The height of wheat plants, the number of spikes, the number of grains per ear, the weight of 1000 grains, and the overall yield exhibited a significant negative correlation with the density of B. japonicus. At a density of 150 B. japonicus plants per square meter, the wheat yield decreased by 38.24% compared to the control group. The equation y=1.240,4x^0.685,3 might more accurately represent the relationship between the density of B. japonicus and the wheat yield loss rate. A density of 0.76 plants/m² of B. japonicus indicated the economic threshold for UAV management of this species. 【Conclusion】 Consequently, preventive measures should be taken if the sustained density of B. japonicus damage in the field exceeds 0.76 plants/m².