Nanocrystalline zinc ferrite (ZnFe 2 O 4 ) is synthesized by high-energy ball-milling after 12h from a powders mixture of zinc oxide (ZnO) and hematite (α-Fe 2 O 3 ) with balls to powders mass ratio of 20:1. X-ray diffraction, vibrating sample magnetometer (VSM), the Mössbauer spectrometry and photoluminescence (PL) are used to characterize the samples. Rietveld analysis and VSM measurements show that the powder has an average crystallites size of 10nm and a ferrimagnetic behavior with a saturation magnetization of 30emu/g. After annealing at 700°C, the lattice parameter reduces from 8.448 to 8.427Å and the sample transforms into a superparamagnetic behavior, which was confirmed as well by the room temperature Mössbauer spectrometry. Different mechanisms to explain the obtained results and the correlation between magnetism and structure are discussed. Finally, the broadband visible emission band is observed in the entire PL spectrum and the estimated energy band gap is about 2.13eV.