In the current research, Magnesium oxide II (MnO2) nanostructures were prepared by chemical route from hydro manganese chloride salt using Potassium hydroxide as reducing agent. X-Ray diffraction (XRD), SEM and Fourier transformation infrared (FTIR) used to characterize both particle size and structure of MnO2 nanoparticles. XRD results confirmed impurity of synthesized powder with α-MnO2 as predominant phase. The average particle size of manganese dioxide was in the range 25 -30 nm. Photographs of scanning electron microscope (SEM) showed two hierarchical structures, cluster agglomeration and chain appearance.