Abstract: Muddy water irrigation has been limited to a wide application during agricultural production in recent years. Current challenges also remain on the water shortage and soil salinization in the arid and semi-arid regions. In this study, a series of experiments was conducted on a one-dimensional soil column infiltration in the laboratory. A systematic investigation was also made to explore the effects of different salt contents (S0: 0.80 g/kg, S1: 4.81 g/kg, and S2: 9.45 g/kg) and biochar addition amounts (B0: 0, B1: 0.5%, B2: 1%, and B3: 2%) on the soil water transport, salt ion distribution and leaching under clear water (ρ0: 0) and muddy water (ρ1: 4%) infiltration. The results showed that the cumulative infiltration amount significantly decreased with the increase of salt content (S) and biochar (B). Compared with the clear water (ρ0), the turbid water (ρ1) was reduced by 18.05% to 31.57%. The medium (S1) and high salt (S2) treatments were reduced by 9.40% to 18.58% and 15.38% to 23.86%, respectively, compared with the low salt (S0) treatment. The addition of biochar (B1/B2/B3) was reduced by 0.75% to 21.16%, compared with no addition (B0). The Kostiakov model (coefficient of determination (R²)>0.88, root mean square error <0.09 cm/min) was more suitable to simulate the infiltration rate than the Philip model. Its parameter K decreased with the increase of S and B, while α was the opposite. The distance of the wetting front migration (F) and time (t) were followed by the power function. The turbid water prolonged the time to reach the bottom of the soil column increased by 10.50% to 27.93%. The S and B further delayed the migration. The fitting parameters C and D were negatively exponentially correlated with S and B (R² > 0.92). The soil profile analysis showed that the moisture content decreased with depth, while the electrical conductivity increased. The turbid water was reduced the average moisture content by 0.52% to 4.37%, whereas, the electrical conductivity increased by 1.78% to 16.74%; The moisture content was reduced by 9.09% to 11.59% in the high salt (S2), leading to a sharp increase in the electrical conductivity by 215.21% to 314.95%; While the biochar (B3) increased the moisture content by 2.61% to 5.53%, whereas, the electrical conductivity was reduced by 10.23% to 23.80%. Except for the soil potassium ions (K⁺), the contents of soil calcium ions (Ca²⁺), magnesium ions (Mg²⁺), sodium ions (Na⁺), sulfate ions (SO₄²⁻), chloride ions (Cl⁻), and bicarbonate ions (HCO₃⁻) all increased with the increase in the salt content. There was a more significant increase in the muddy water than that in the clear water treatment; While the biochar addition significantly reduced the contents of Na⁺ and Cl⁻, thus promoting the retention of K⁺ and Ca²⁺. The high salt content (S2) exacerbated the salt accumulation to reduce the volume of the leaching solution. The treatment with ρ1S2B3 showed the highest leaching solution conductivity, with an average conductivity of 88.32 mS/cm. The sediment concentration and salt content of turbid water inhibited the water transport due to the pore blockage and osmotic pressure. The biochar optimized the water salt balance to regulate the ion adsorption and pore structure. The finding can also provide a theoretical basis for the synergistic improvement of the turbid water irrigation and biochar in saline alkali land.