Zn2+ ion doped Fe3O4 nanoparticles based on iron sand have been successfully synthesized by coprecipitation method at low temperature. The starting materials were iron sand, ZnCl2, HCl, and NH4OH. Characterizations were conducted by means of X-Ray Flourescence (XRF), X-Ray Diffraction (XRD) and digital capacitance meter AD5822. XRF identification confirms that the elemental composition of all samples is appropriate with the stoichiometry calculation. Phase formation identification by using High Score Plus and DDView+PDF2 software reveals that all samples crystallize in cubic spinel structure. Rietveld refinement analysis bymeans of Reitica yields the doping of Zn2+ ion on Fe3O4 increases the lattice parameter with crystal size in the order of nanometer. This is in line with theoretical predictions as a consequence of the influence of Zn2+ ionic radii that replace Fe2+. Furthermore, dielectricity analysis shows that the higher the amount of Zn2+ doped Fe3O4 nanoparticles the higher the dielectric constant. This mechanism is ionic polarization phenomenom as consequence of the decreasing in the crystal volume and the atomic distance that lead to increase the moment of dipole.