We prepared the hydrothermal method to synthesize MnO 2 nanorods with controlled structure. KMnO 4 and HCl with the various molar ratio (1:2,1:6,1:8) reacted at 160°C for three hours to form MnO 2 nanorods. The study found that changing the molar ratio can control the structure and morphology of MnO 2 . The result revealed that MnO 2 formed in nanorod microstructures with different crystallographic structure and phase composition of each molar ratio. The diffraction peaks observed at 2θ values of 28.9°, 37.8°, 40.9°, 49.7° and 60.5° respectively indexed to (110), (101), (200), (411) and (521) plane reflections of a tetragonal phase of β -MnO 2 and α-MnO 2 . The characterization of the morphology showed that the diameters of nanorod microstructures of MnO 2 ranging from 30 to 145 nm with length ranging from 0.5 to 3 μm. These MnO 2 nanorods product would be potentially used in energy storage devices.