In this study, preparation, characterization and adsorption properties of the magnetic nanocomposite Fe3O4@SiO2@Ni2+ made by chemical co-precipitation method were investigated. The structure of synthesized nanocomposite was characterized by using FT-IR, XRD, VSM, FE-SEM, EDX-MAP, TGA, BET, and ICP-OES analyses. The introduced nanocomposite exhibited a great tendency towards the azo and anionic dyes in aqueous media. The adsorption parameters were evaluated to find the optimal conditions of pH= 7, T= 293 K, amount of adsorbent= 10 mg, t= 10 min, and the initial concentration of Acid violet 5 dye= 20 mg/L. The isotherm and kinetic models were investigated by using adsorption equilibrium data. The magnetic nanocomposite gave a high maximum adsorption capacity (qmax) and adsorption percentage (%A) under optimal conditions.