In this work, core-shell structured microspheres with Ni cores and Sn6O4(OH)(4) nanoshells have been successfully synthesized by a solvothermal deposition method. The crystal structure, microstructures and electromagnetic (EM) properties of the samples were investigated by X-ray diffraction, scanning electron microscopy, energy disperse X-ray spectrometry, Fourier transform infrared (FT-IR), transmission electron microscope (TEM) and a network analyser. The Ni/Sn6O4(OH)(4) composite microspheres show better microwave absorption properties than those of pure Ni microspheres. An obvious multiple reflection loss phenomenon was observed with the increase of matching thickness. A minimal reflection loss (RL) as low as -32.4 dB was observed at 13.2 GHz with the absorber thickness of 5.0 mm. The enhanced microwave absorption performances of Ni/Sn6O4(OH)(4) composite microspheres were due to good electromagnetic impedance match, geometrical factors, and unique core-shell structure. (C) 2014 Elsevier B.V. All rights reserved.