In this paper, we report a simple and convenient method for the synthesis of α Fe2O3 nanoparticles via hydrothermal process followed by thermal decomposition using the new iron precursor, which was obtained by mixing of benzoic acid (BA) and Fe(NO3)3∙3H2O in water as the solvent. Two products with almost similar morphologies and sizes were obtained by changing the calcination temperature (500 and 600ºC) for 2 h in the air atmosphere. They were named Fe 500 and Fe 600, respectively, and characterized by Fourier transform infrared (FT IR) and ultraviolet visible (UV Vis) spectroscopy, X-ray powder diffraction (XRD), Energy dispersive spectroscopy (EDS) and transmission electron microscopy (TEM). FT IR, UV Vis, XRD and EDS results confirm the formation of α Fe2O3 phase. Also, TEM images confirm that the size of the products is less than 100 nm.