Gold nanoparticles modified with poly(2-methyl-2-oxazoline) have been prepared via chemical reduction of HAuCl4 by NaBH4. The gold nanoparticles were homogeneously dispersed in poly(vinyl chloride) as a polymer matrix by the miscibility between the protecting polymer of the nanoparticle and the polymer matrix. Differential scanning calorimetry and UV-vis absorption measurement clearly showed that the miscibility played an important role for incorporation of the metal nanoparticles in the polymer matrix.