Litchi-like core-shell magnetic composite microspheres decorated on their surface with silver (Ag) nanoparticles (P(MMA-AA-DVB)@Fe3O4@Ag), were synthesized through a thermal decomposition method and carefully characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, vibrating sample magnetometry and thermogravimetric analysis. The prepared composite microspheres were used as a catalyst for the reduction of methyl orange in the presence of sodium borohydride (NaBH4). The study revealed that methyl orange was completely reduced within 10min and there was no remarkable change in the catalytic activity of the composite particles after five catalytic reaction cycles. In addition, the prepared catalyst was easily recycled using a magnet. Such excellent catalytic activity was attributed to the small size and great uniform distribution of Ag nanoparticles on the surface of the composite particles. The method reported here offers an effective approach for the fast catalytic reduction of the methyl orange dye, and also provides a novel idea for the rapid catalysis of other dyes.Graphical AbstractLitchi-like core-shell magnetic composite microspheres decorated on their surface with silver nanoparticles (P(MMA-AA-DVB)@Fe3O4@Ag), were synthesized for the catalytic reduction of methyl orange, and through simply adjusting the dosage of polymer particles, the coating amount of Fe3O4 nanoparticles on the polymer surface could be effectively controlled. [GRAPHICS] .