Cesium is a rare metal of paramount importance across various domains.Despite abundant cesium resources in Qinghai-Tibet Plateau salt lakes, concentrations remain low, and existing adsorbents generally exhibit limited adsorption capacities.Consequently, there is a pressing need for the development of an adsorbent capable of effectively separating and efficiently extracting cesium ions.This work utilizes the unique functional groups and neg. charge characteristics of the two-dimensional (2D) MXene surface to promote the precipitation and crystallization of 2D layered double hydroxides (LDH), thereby enabling the in-situ growth of hydrotalcite on the MXene surface and synthesizing a 2D/2D stacked Na+-MXene/LDH composite.The results indicated that Na+-MXene/LDH exhibited enhanced sp. surface area and interlayer spacing, introducing addnl. active sites that significantly improved Cs+ adsorption capacity, with a maximum recorded uptake of 961.5 mg/g, surpassing previously reported MXene-based adsorbents.Adsorption tests conducted on brines from four hydrochem. types of salt lakes on the Qinghai-Tibet Plateau revealed that Na+-MXene/LDH displayed the highest distribution coefficient (KCsd) of 31.92 x 104 mL/g in Dong Taijnar Lake, demonstrating a strong affinity and selectivity for Cs+.The mechanisms underlying the enhanced adsorption performance were elucidated.Addnl., ecol. safety assessments, along with evaluations of microbial diversity and water quality in Qinghai Lake, confirmed that Na+-MXene/LDH preserved microbial diversity and stabilized community structures, thereby underscoring its non-toxic and environmentally friendly characteristics.This research provides a promising adsorbent for cesium extraction from brine, with potential applications in water purification and ecol. restoration.