Abstract: Spinel LiMn₂O₄ is synthesized by way of modified solid-phase out of Mn(OH)2 made in the lab. The electro -chemical properties of spinel LiMn₂O₄ are systematically researched from the aspects of synthesizing temperature, Li/2Mn ratio and heating rate. The SEM, XRD and electric property tests show that the product synthesized is of spinel structure and the diffraction peaks are consistent with the standard pattern of LiMn₂O₄. The following are the optimal synthesizing conditions for spinel LiMn₂O₄:the synthesized temperature is 760 ℃; Li/2Mn ratios is Li/2Mn=1.05;heating rate is 5 ℃/min. The initial cycle performance of the AA lithium-ion battery can reach 100mAh/g.