[en] Conductive polymer, polyaniline and its nanocomposite have attracted much attention due to their potential applications. The incorporation of gold nanoparticles to ultra thin polyaniline film has been done and its effects on structural and optical properties have been discussed. The SEM and TEM spectra for polyaniline and gold nanocomposite polyaniline clearly show different states of surface morphology of two samples. FTIR and TEM spectra display the presence of gold nanoparticles in the nanocomposite polyaniline sample. The increase of conductivity and change of band gap in gold nanocomposite film have been observed. The band gap calculated for polyaniline and gold nanocomposite polyaniline films are 2.90 eV and 2.73 eV, respectively. Intense photoluminescence effect is observed in gold nanocomposite samples. (author)