Severe water scarcity and soil salinization have emerged as persistent ecological challenges threatening global agricultural sustainability. In this study, a molecularly engineered functional crosslinking agent was successfully synthesized through molecular-level surface modification of gamma-alumina nanoparticles. Subsequently, a tragacanth gum-g-polyacrylic acid / acrylic acid-aluminium oxide (TG-g-PAA/AA-Al2O3) exhibiting dual anti-leakage and salt-resistant properties was fabricated via aqueous solution polymerization using acrylic acid as the primary monomer. Systematic characterization revealed that the incorporation of 0.8 wt% bifunctional polymeric composite significantly enhanced material performance, demonstrating 18.4 % improvement in anti-leakage properties and 24.7 % improvement in salt-resistant compared to the control group. This innovative material integrates water conservation with saline soil remediation, offering dual-functional benefits for arid region management: simultaneously addressing water resource preservation while facilitating agricultural land reclamation. The proposed methodology establishes a novel theoretical framework for coordinated management of water and soil resources in drought-prone ecosystems, providing new insights for sustainable agriculture development in arid/semi-arid regions.