In this work, magnetically recyclable lithium manganese oxide ion sieves (H_1.6(Al_xMn_1−x)_1.6Fe_yO₄, HMO-x–y) with enhanced Li⁺ adsorption capability were synthesized by Al–Fe co-doping via hydrothermal reactions. XRD characterization showed that the Al–Fe co-doped sample maintained the spinel crystal structure of the undoped HMO-0–0. SEM imaging and EDS mapping indicated that a rough surface with a granular convex morphology was obtained and the doping elements Al and Fe were uniformly dispersed in the grains. Magnetic studies revealed that HMO-0.3–0.1 exhibited a magnetization value of 2.86 emu g⁻¹ and could be separated from solutions effectively using a magnet. Li⁺ adsorption analysis showed that the equilibrium adsorption capacity of Al–Fe co-doped HMO-0.3–0.1 reached 45.31 mg g⁻¹, which was larger than that of HMO-0.3–0 (33.39 mg g⁻¹) with only Al-doping. In addition, HMO-0.3–0.1 exhibited excellent cycling performance and the Li⁺ adsorption capacity was maintained over 95% after five cycles. Compared with the Al-doped or Fe-doped sieves, the Al–Fe co-doped lithium ion sieve with excellent adsorption performance and characteristics that can be separated from solutions by a magnetic field is generally regarded as the most promising adsorbent for recovering lithium from salt-lake brines.