In this paper, ultrasonic technique and a biocompatible coupling agent were used for the surface modification of ZrO2 nanoparticles (NPs). The grafting of N-trimellitylimido-l-leucine as bioactive and biocompatible coupling agent on the surface of ZrO2 NPs was confirmed by Fourier transmission infrared spectroscopy and thermogravimetric analysis. Subsequently, the modified NPs were incorporated into the poly(amide-imide) (PAI) matrix through good dispersion. Therefore, poly(amide-imide)/nano-ZrO2 nanocomposite (PAI/nano-ZrO2) was synthesized via ultrasonic technique. Field emission scanning electron microscopy and transmission electron microscopy images of the obtained PAI/nano-ZrO2 illustrated nanostructured morphology. Then, PAI/nano-ZrO2 was used as a nano-filler and was embedded into the polyvinylpyrrolidone (PVP) in various weight percent to form PVP NCs to improve its properties. These NCs were investigated by different analyses. Change in the results of analysis when compared to the pure PVP confirmed that there are good interactions between nano-filler and the PVP matrix as a result of hydrogen bonding. The thermal stability of the PVP was enhanced with the addition of small amounts of nano-filler. Also, the incorporation of the PAI/nano-ZrO2 influenced the UV-Vis absorption of the pure PVP.