Ordered mesoporous MoO2 is prepared employing silica KIT-6 as hard template. Electrochemical quartz crystal microbalance is utilized to investigate the charge storage mechanism of mesoporous MoO2 in aqueous LiOH electrolyte solution. The dominating working ions are proved to be Li+ ions. Mesoporous MoO2 exhibits excellent supercapacitive behavior in the potential range of −1.2 to −0.5 V vs. SCE, rendering it a promising anode material for aqueous supercapacitors.