The thermal treatment method was employed to prepare barium hexaferrite (Fe6O8/BaFe6O11) nanostructure. This method was attempted to achieve higher homogeneity of the final product. Specimens of barium hexaferrite nanostructure were characterized by various experimental techniques including X-ray diffraction (XRD), Electron paramagnetic resonance (EPR). X-ray diffraction results showed that there was no crystallinity in the predecessor and it had stillamorphous phase. The formations of crystalline phases of barium hexaferrite nanostructures started from 673 to 973K and the final products had different crystallite sizes ranging from 29 to 48 nm. The formed nanostructures exhibited ferromagnetic behaviours which were confirmed by using a Vibrating sample magnetometer (VSM).