Abstract: A polyurethane/silver sulfide nanocomposite film was synthesized by a biomineralization sim-ulated method. The effect of the Ag₂S nanoparticles on the physical properties of the com-posite was studied by Fourier transform infrared, differential scanning calorimetry (DSC), scanning electron microscopy. The thermal stability of the composite was measured by DSC. The fluorescence emission of the nanocomposite films was found to be very sensitive to Ni(II) ions, with a small amount of Ni(II) ions making the emissions increase dramatically. The films are predicted to have the potential to be developed into excellent sensing films of Ni(II) ions in the water.