Purpose <p>This study investigated the effects of sediment concentration and fertilizer concentration on water-fertilizer-salt distribution under film hole irrigation conditions, aiming to provide a scientific basis for improving irrigation efficiency and reducing salt accumulation.</p> Methods <p>Soil box infiltration tests were performed to investigate the effects of five levels of sediment concentration in muddy water (0%, 3%, 6%, 9%, 12%) and five levels of fertilizer concentration (0, 0.3, 0.6, 0.9, 1.2&#xa0;g L⁻¹) on the cumulative infiltration and the wetting front migration distance. The distribution of water, salt, and nutrients in the wetting body after infiltration was also analyzed.</p> Results <p>The cumulative infiltration and the wetting front migration distance both decreased with increasing sediment concentration and increased with increasing fertilizer concentration. In addition, the increase in sediment concentration led to an increase in ammonium nitrogen, nitrate nitrogen, conductivity, and salt ion within the 0–6&#xa0;cm depth at the end of infiltration. Conversely, the increase in fertilizer concentration reduced Na⁺, Mg²⁺, SO₄²⁻, Cl⁻ and HCO₃⁻ content within the 0–10&#xa0;cm depth, and increased Ca²⁺content and soil conductivity.</p> Conclusions <p>This study reveals that the sediment in muddy water inhibits water transport through physical blockage, reduces nitrogen fertilizer leaching, and the fertilizer solution regulates water-salt migration through ion strength and ion exchange effects. It can provide a theoretical foundation for the efficient use of muddy water resources, as well as coordinated water-fertilizer management under film hole irrigation conditions in saline-alkali areas.</p>