A facile soft-templating method has been successfully developed to prepare mesoporous spinel LiMn2O4 with high crystallinity. The cathode material with narrow pore size distributions significantly enhances charge transfer and reduces lithium ion diffusion length. The mesoporous LiMn2O4 deliver initial discharge capacity of 133.6mAh/g in at a current density of 74mAh/g. After 100 cycles, discharge capacity maintains 109.1mAh/g. At a high current density of 296mAh/g, the mesoporous LiMn2O4 has a high discharge capacity around 102mAh/g. Electrochemical impedance spectroscopy (EIS) testing showed that the mesoporous LiMn2O4 has a higher Li-ion diffusion coefficient (DLi) than bulk LiMn2O4. Furthermore, LiMn2O4//graphite full-cell is fabricated. It also exhibits good cycling capability with specific capacity of ∼90mAh/g after 40 charge/discharge cycles.