<p>This study conducted a two-year field experiment to explore the effects of sediment concentration (ρ: 3, 6, 9&#xa0;kg·m⁻³), irrigation level (W: 50%–65%, 60%–75%, 70%–85% field capacity (FC)), and nitrogen application rate (N: 100, 160, 220&#xa0;kg·ha⁻¹) on the dynamics of dry matter accumulation, plant nitrogen concentration, and yield of winter wheat under Yellow River muddy water irrigation conditions to clarify the dynamic accumulation of dry matter, nitrogen nutrition diagnosis methods, and optimal management mode of winter wheat under Yellow River muddy water irrigation. The results showed the Richards model to have the ability to accurately simulate the dynamics of dry matter accumulation (fitting coefficient of determination (<i>R</i>²) &gt; 0.97), while the T5 treatment (with a sediment concentration of 6&#xa0;kg·m⁻³, irrigation level of 60%–75% FC, and nitrogen application rate of 160&#xa0;kg·ha⁻¹) had the highest dry matter accumulation (13.90–14.05&#xa0;Mg·ha⁻¹), with a maximum growth rate of 13.55&#xa0;Mg·ha⁻¹·(℃·d)⁻¹. The critical nitrogen concentration dilution curve that was constructed based on aboveground dry matter and nitrogen concentration data was well validated (<i>R</i>² &gt; 0.79), and the leaf SPAD value had a significantly positive correlation with the nitrogen nutrition index (NNI) (<i>R</i>² = 0.576–0.912), which indicates that SPAD can be used for rapidly estimating NNI. The T5 treatment had the highest yield (9.78–9.81&#xa0;Mg·ha⁻¹) and nitrogen fertilizer agronomic efficiency (28.06&#xa0;kg·kg⁻¹). According to the TOPSIS method for the comprehensive evaluation of a variety of indicators, T5 treatment has the highest comprehensive score. This study provides a theoretical basis for green water and nitrogen-efficient management and real-time nitrogen nutrition diagnosis of winter wheat in arid and semi-arid areas in Northwest China.</p>