The goal of the current paper was a synthesis of Amino-functionalized FeO@SiO core-shell magnetic nanoparticles as a unique efficient photocatalyst for removing organic dyes from aqueous environments. The magnetic FeO@SiO core-shell was produced by a silica source to avoid aggregation by the co-precipitation method. Next, functionalized by using 3-Aminopropyltriethoxysilane (APTES) via a post-synthesis link. The chemical structure, magnetic properties, and shape of the manufactured photocatalyst (FeO@SiO-NH) were described by XRD, VSM, FT-IR, FESEM, EDAX, and DLS/Zeta potential analyses. The XRD findings approved the successful synthesis of nanoparticles. The photocatalytic activity of FeO@SiO-NH nanoparticles was examined for MB degradation and the degradation performance was about 90% in the optimum conditions. Also, the cytotoxicity of FeO, FeO@SiO core-shell, and FeO@SiO-NH nanoparticles was examined on CT-26 cells using an MTT assay, the finding has shown that nanoparticles can be used for inhibiting cancer cells.