H2TiO3 (HTO) is one promising type of lithium-ion sieves (LISs) due to its theoretical adsorption capacity, stability and selectivity, but its actual adsorption ability is restricted. Since the larger radius of Cu ions than that of Ti4+, Cu doping was performed in this work for the purpose to improve adsorption performance by enlarging Li+ transport channels. The doping content of Cu as well its effect on structures, properties and adsorption performance of LISs were examined by various techniques. After trace doping of Cu, the hydrophilicity and specific surface area of HTO-Cu-0.04 (0.04 is the doping content) were improved, which can increase adsorption sites and accelerate Li+ diffusion process. And thus, HTO-Cu-0.04 owned enhanced adsorption capacity than HTO (35.58 vs 22.41 mg·g−1 at 298 K) and some other metal doped HTO in literature despite different adsorption conditions. The Li+ adsorption on HTO-Cu-0.04 is spontaneous and endothermic, following Langmuir isotherm model and pseudo-second-order kinetics model. The adsorption selectivity was examined in the simulated brine of Li+, Na+, K+, Ca2+, and Mg2+, which was analyzed by the distribution coefficient (Kd,Li) and separation factor (αMLi). After five adsorption–desorption cycles, the adsorption capacity of HTO-Cu-0.04 amounts to 95.8 % of the initial value, showing high stability. This work provides guidance for doping engineering to increase Li+ diffusion channels and hydrophilicity of LISs for improved Li+ recovery.