Several core-shell nanocomposites composed of Fe3O4 microspheres, Polypyrrole and silver were fabricated here by a series of wet chemical methods. The as-prepared nanocomposites were further used in adsorption and photodegradation of azo dyes. The chemical properties of the products were characterized by a series of techniques and equipment. The adsorption and photocatalytic activities of the obtained core-shell heterostructure were studied by controlled experiments. It was found that Fe3O4@PPy nanostructure exhibited the highest removal abilities towards organic dyes in aqueous solution among the as-prepared samples. The final removal ratio is 86.2% and 80.4% for Methyl Orange and Orange II aqueous solutions, respectively. Deposition of Ag nanoparticles was employed here to investigate the transportation and separation of photo-induced charges on the surface or interface of Fe3O4@PPy under UV illumination. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B. V. and The Society of Powder Technology Japan. All rights reserved.