Abstarct: Firstly, in this research magnetite diatomite nanoparticle was produced from raw diatomite and secondly this novel adsorbent was used for removal of Ni(II), Cd(II) ions and Basic Blue 41 dye in the laboratory. So, for physicochemical characterization of this magnetite nanoadsorbent, several analysis consist of SEM, TEM, AFM, XRD, XRF, XRD and FT-IR were done. baxse on SEM, TEM and AFM analysis the spherical morphology and uniform dimensions smaller than 100 nanometers is obviously for magnetite diatomite nanoparticle. In XRF analysis of magnetite diatomite nanoparticle was silica and iron is more than 8 and 28%, respectively. The obtained results of XRD analysis show that Fe(II) and Fe(III) ions were coated on magnetite diatomite nanoparticle. baxse on FT-IR analysis hydroxyl (OH¯) functional group is major function for adsorption of water pollutants. After characterization of physicochemical features, the application of magnetite diatomite nanoparticles for removal of Ni(II), Cd(II) ions and Basic Blue 41 dye in the laboratory in the batch system. So, the effecting of pH, adsorbent dosage, initial concentration, temperature and time parameters on adsorption process were considered. Optimal pH for Ni(II), Cd(II) ions and Basic Blue 41 dye is 4, 6 and 2, respectively. Obtained results show that magnetite diatomite nanoparticles have suitable adsorption efficiency for removal of Ni(II), Cd(II) ions and Basic Blue 41 dye as 58, 52 and 98%, respectively. Adsorption processes of Ni(II), Cd(II) ions and Basic Blue 41 dye by magnetite diatomite nanoparticles were considered as kinetically and equilibrium. In equilibrium mode Longmuir isotherm have good fitting with experimental data for three pollutants. In kinetic state semi second order kinetic for Ni(II), Cd(II) ions and semi first order kinetic for Basic Blue 41 dye have best fitting with experimental data. The obtained results from thermo-dynamical consideration show that the adsorption of Ni(II), Cd(II) ions is endothermic and the adsorption of Basic Blue 41 dye exothermic.