This research proposes an efficient method for depositing Fe-Ni nanoparticles on Al2O3 microparticles to decompose containments in ground water, such as chloroform and trichloroethylene. The Fe-Ni nanoparticles can be deposited onto the surface of Al2O3 microparticles by electroless plating technique. The reasons why the Fe-Ni nanoparticles would be deposited on the surface of Al2O3 microparticles is to avoid the agglomeration of Fe-Ni nanoparticles due to their surface effect and magnetic property. The results show that the sizes of Fe-Ni particles on Al2O3 particles are between several and several hundreds of nanometers, the contents of Fe and Ni in Fe-Ni nanoparticles can be adjusted from 8 to 60 at.% for Fe and 40 to 92 at.% for Ni, the specific surface area of Fe-Ni nanoparticles can reach to 117 m(2)/g, and the reaction mechanism of dechlorination of chloroform of 2 mg/L by Fe-Ni/Al2O3 particles of 5 g/L appears to be pseudo first order with a half life of 0.7 h and the half life is 0.25 h for the dechlorination of trichloroethylene of 2 mg/L. (c) 2006 Elsevier B.V. All rights reserved.