KMn8O16 nanorods were prepared through a facile hydrothermal method by using KMnO4 and MnSO4 as reactants. The KMn8O16 samples synthesized at different temperatures (100-160 degrees C) were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and its electrochemical properties were tested by galvanostatic charge/discharge system. The effect of reaction temperature on the morphology and electrochemical properties was investigated. As electrode materials for the lithium ion battery cycled between 1.5 and 4.2 V, the KMn8O16 nanorods synthesized at 160 degrees C show the highest reversible discharge capacity (160.1 mA h/g even after 50 cycles at current density of 50 mA/g) and the best cycling stability. These results indicate that the KMn8O16 nanorods could be a promising cathode material for lithium ion batteries.