A novel methodology for the synthesis of the water-dispersible Fe3O4 particles modified by β-cyclodextrin (denoted as Fe3O4@β-CD) was proposed using N2 plasma-induced grafting technique. The Fe3O4@β-CD composites were applied in the removal of inorganic and organic pollutants from aqueous solutions. The characteristic results of Fourier transform infrared spectroscopy and thermogravimetric analysis showed that β-CD was grafted onto Fe3O4 particles. The grafted β-CD on Fe3O4 particles contributed to an enhancement of the adsorption capacity because of the strong abilities of the multiple hydroxyl groups and the inner cores of the hydrophobic cavity in β-CD to form complexes with metal ions and organic pollutants. The Fe3O4@β-CD composites had good dispersion in water and could be separated from solution by magnetic separation. The adsorption of 1-naphthylamine on the Fe3O4@β-CD composites was dependent on pH and ionic strength. The results indicate that the Fe3O4@β-CD composites are the promising material for the separation and preconcentration of inorganic and organic pollutants from aqueous solutions in environmental pollution cleanup.