In this study, we have presented a smart core/shell nanocomposite: intelligent polymer modified iron nanoparticles (PNZVI), which can be easily synthesized by the microemulsion method followed by a in-situ surface-radical graft polymerization. The structure and composition of the nanocomposite particles prepared were characterized by transmission electron microscope (TEM), X-ray diffractometer (XRD), Fourier transfer infrared spectrometer (FTIR) and thermal analysis (TG). The PNZVI exhibited good stability in air since the coating of polymer effectively protected the iron core from oxidation. Furthermore, the stimuli-response of outer polymer layer was capable of creating a stable dispersion of nanoparticles and improving the compatibility of the composite particles with organic pollutant. Batch experiments further confirmed that the prepared PNZVI were capable of effectively reducing trichloroethylene (TCE).