Photoinduced second harmonic generation (SHG) in Au nanoparticle-deposited ZnO nanocrystallite (NC) films was explored by applying bicolor coherent treatment of a Nd-YAG laser with wavelength 1.06 µm and its SHG. We have established that coexistence of the ZnO and Au nanoparticles gives a substantially larger SHG output with respect to pure ZnO NC deposited on the glass substrate. It was established that the value of the second order susceptibility is about 23 pm V-1. Better nonlinear optical susceptibilities were obtained during phototreatment at temperatures near 30-35 °C for the Au doped samples. The samples without gold NCs are temperature independent. Generally an increasing temperature leads to a decrease of the optical SHG.