The electronic structure and chemical bonding nature of spinel-type Li1.33Mn1.67O4 system was calculated by a discrete-variational (DV)-Xalpha clusters method. In order to elucidate the reason for the selective exchange of Li+ ions, the bonding natures between tetrahedral and octahedral Li sites of the Li1.33Mn1.67O4 were compared. Li in the manganese oxides is highly ionized in both sites, but the net charge of Li was greater for tetrahedral sites than octahedral. These calculations suggest that the tetrahedral sites have higher Li+/H+ exchangeability than the octahedral sites, and are preferable for the selective adsorption for Li+ ions.