It was shown the possibility to improve ZnO crystal lattice by powerful Nd:YAG laser radiation. The measurements of photoluminescence spectra have shown the decrease of the spectra intensity of defect related band with maximum at 2.4 eV after irradiation by laser. The control of photoluminescence spectra intensity of defect related band was achieved by different laser radiation intensity. Topography studies using atomic force microscope showed smoothing of the surface, as well. The formation of nanocavities on ZnO/Si sample surface at higher laser radiation intensity was detected by scanning electron microscope.