Setting: up interlayers to prevent upward salt movement may effectively manage salt accumulation in the root zone of saline wasteland with high groundwater levels and evaporation. To assess the impact of a biochar interlayer combined with Suaeda salsa on saline wasteland improvement, field experiments involving the burial of biochar interlayers within a 40 cm soil layer were conducted over two years. Four different amounts of biochar were tested: 0 Mg ha-1 (CK), 15 Mg ha-1 (M1), 45 Mg ha-1 (M2), and 75 Mg ha-1 (M3). The results indicated that the biochar interlayer treatment increased soil spatial heterogeneity and altered the spatial distributions of soil water, salt, and fertilizer. In the 0-50 cm soil layer, this treatment notably increased the soil moisture content by 5.33 %-20.69 %, and the soil water content increased with increasing biochar amount. The soil salinity in the 0-40 cm soil layer decreased by 13.85 %-40.74 %, and with increasing biochar content, it first decreased but then increased. The biochar interlayer treatment also increased the soil nitrate nitrogen concentration by 3.68 %-23.87 % and reduced the deep leaching loss of nitrogen. There was a positive correlation between root morphology and the soil nitrogen content, increases in root morphology parameters of 3.26 %-27.52 %, respectively. The root system absorbed more water, salt, and nutrients from the biochar layer, increasing the total biomass by 22.12 %-65.92 %, and the total salt absorption capacity increased by 30.62 %- 85.03 %. Hence, biochar interlayer (45 t ha-1) represents an efficient approach for the ecological development of saline wasteland, with promising application prospects in extremely arid regions.