Me-Zr-O systems were studied with X-ray Radial Electronic Density Distribution (RED) method. This method is based on the relation between the radial electronic density distribution function and intensity of coherent scattering of X-ray in the diffraction experiment. The intensity of scattering was measured for a wide range of angles using monochromator and CuK alpha radiation. RED curves was made by resolving in sum of Gauss function. Data on the known oxides and hydroxides structures, such as interatomic distances (r) and coordination number (Z) were used for the calculated curves. The values r and Z were calculated from the data of structural type, spatial group, coordinates of atoms and parameters of cell. For Fe-Zr-O system it has been demonstrated that all samples have similar structures, which related to that of cubic alpha-ZrO2. The model with statistical arrangement of Fe3+ cations, vacancies in the cation and anion sublattices and modification of anion sublattice with OH- groups is admitted as most probable. Numbers of cation and anion vacancies and number of OH-groups were evaluated using experimental RED curves of samples.