Increasing plant density and reducing nitrogen application can improve wheat yield by adjusting root traits, photosynthesis, and nitrogen accumulation. Higher plant density led to decreased individual plant root traits but enhanced them in the population. Photosynthesis was negatively affected by plant density but improved with higher nitrogen levels. Nitrogen accumulation per plant decreased with density but increased with nitrogen application. Yield could be maintained or improved by reducing nitrogen and increasing plant density. Adjusting plant density can help improve wheat yield with less nitrogen.