The research of ZnO has been at high interest for quite a long time due to its unique optical, piezoelectric and magnetic properties, as well as potential applications such as: light emitting diodes, near-UV or UV laser diodes and solar cells. The aim of the present work is to study the possibility of Zn nanoparticles formation by UV laser at the irradiated surface of ZnO crystal. The increase of ZnO single crystal electrical conductivity up to 250 times after irradiation by Nd:YAG laser was observed. At the same time, the improvement of ZnO crystal quality by laser intensity 3.2 MW/cm2 takes place. The further increase of laser intensity led to emergence of cracks on the irradiated surface of the crystal and the dramatic decrease of the total photoluminescence intensity, especially, around the cracks. At the laser intensity 290.0 MW/cm2 Zn nanoparticles were formed. The formation mechanism of Zn nanoparticles by the laser is explained by Thermogradient effect. According to the effect, laser radiation leads to generation and redistribution of point defects. In our case, the generation of zinc interstitials (Zni) and zinc vacancies (VZn) pairs takes place. It is explained by low formation energy of these defects in ZnO crystal in comparison to other native point defects. Therefore, it is more likely that during irradiation VZn and Zni are formed. The gradient of temperature field induced by laser radiation leads to redistribution of the point defects and the drift of Zni atoms to the irradiated surface of the sample takes place. This was proved by huge increase of electrical conductivity up to 250 times. Moreover, the topography change was not observed till laser intensity 290.0 MW/cm2. The increase of Zni atoms’ concentration at the irradiated surface of the sample at certain concentration leads to the agglomeration of Zni atoms forming Zn nanoparticles.