A new plasmonic photocatalyst of Ag-AgI/Fe3O4@SiO2 was prepared by deposition-precipitation and photoreduction method. The catalyst exhibited efficient photocatalytic activity for the degradation of rhodamine B dye and 4-chlorophenol under visible light irradiation. The degradation rate of rhodamine B and 4-chlorophenol over Ag-AgI/Fe3O4@SiO2 was about 10 times and 4.1 times faster than that of N-TiO2. respectively. The catalyst could be easily recovered due to its paramagnetic property. X-ray diffraction, X-ray photoelectron spectroscopy and transmission electron microscope were used to characterize the catalyst. The specified photocatalytic reaction and the study of electron paramagnetic resonance verified that both the O-2(-center dot) and (OH)-O-center dot radicals were the main active species in this reaction. (C) 2010 Elsevier B.V. All rights reserved.