Poly(cyclotriphosphazene-co-4,4'-sulfonyldiphenol) (PZS) nanospheres with average diameter of 410nm were synthesized rapidly at room temperature and then homogeneously decorated with Pd nanoparticles through an inorganic reaction in supercritical carbon dioxide-ethanol solution using PdCl2 as a metal precursor. The resultant Pd/PZS nanocomposites were morphologically and structurally characterized by means of scanning electron microscopy, transmission electron microscope equipped with energy-dispersive X-ray spectroscopy, and X-ray diffraction techniques. Characterization results showed that the Pd nanoparticles with good dispersibility could be well anchored onto the surfaces of the PZS nanospheres and the size of Pd nanoparticles could be controlled easily by varying the ethanol-reduction time. (C) 2011 Elsevier B.V. All rights reserved.