Driven by the increasing global demand for lithium, significant attention has been directed toward developing efficient technologies for lithium extraction from Salt Lake brines. Li_1.6Mn_1.6O₄ spinel shows high lithium selectivity and notable theoretical uptake capacity, indicating strong application potential in lithium extraction. However, the industrial application of this material is limited by its strong Jahn-Teller effect and manganese dissolution loss. In this study, LiOH and MnCO₃ were selected as the raw materials and La₂O₃ was used as the doping modifier. The La³⁺-doped Li_1.6Mn_1.6O₄ precursor (La-LMO) was fabricated through hydrothermal and high-temperature solid-phase synthesis techniques. Then La³⁺ doped H_1.6Mn_1.6O₄ lithium ion-sieve (La-HMO) was prepared by pickling. The materials' structure and morphology were examined using XRD, SEM, TEM, and XPS techniques. La³⁺ doping does not alter the spinel structure of LMO but reduces Mn³⁺ content, mitigates the Jahn-Teller effect, lowers the manganese dissolution rate, and enhances structural stability. Adsorption of Li⁺ onto La-HMO follows pseudo-second-order kinetics and fits the Langmuir model, suggesting homogeneous monolayer adsorption driven by chemisorption. In the lithium extraction experiment from the brine of West Tai Kinel Salt Lake, La-HMO demonstrated high adsorption capacity and superior selectivity for Li⁺. After five cycles, La-HMO maintained an adsorption capacity of 33.10 mg/g, higher than the 26.80 mg/g for undoped HMO. The manganese dissolution rate dropped from 4.65 % to 4.04 %. The study significantly improved the adsorption properties and structural stability of HMO by doping La³⁺, which has broad application prospects in the separation and extraction of lithium resources in Salt Lake.