Magnetic iron oxide nanoparticles were successfully prepared by one-pot low temperature method and it was widely investigated. The phase purity and the crystal structure of the as-prepared samples were characterized by XRD and further determined by Rietveld analysis. The crystallite size was calculated using Debye Sherrer formula, and it shows the range of 15-20 nm. The lattice parameters of the samples were measured by Rietveld analysis. The morphology of the products was studied by HR-SEM and it was confirmed by HR-TEM. The observation showed that the morphology of the nanostructures changed from nanospheres into nanorods as the temperature was varied, while their size was also increased. The formation of pure α-Fe2O3 samples was further confirmed by EDX analysis. The optical properties and the band gap energy were measured by UV-Visible DRS and PL spectra. Magnetic hysteresis (M-H) loops revealed that the as-prepared iron oxide nanoparticles displayed ferromagnetic behavior