Pulsed Laser Ablation in Liquid (PLAL) has become an increasingly important technique for metals production and metal oxides nanoparticles (NPs). This technique has its many advantages compared with other conventional techniques (physical and chemical). This work was devoted for production of alumina (Al2O3) nanoparticles via PLAL technique from a solid alumina target immersed in ethanol at different values of laser fluences in order to study the effect of laser fluences on the optical properties and structure of Al2O3 nanoparticles. The controllability of particle size and size distribution is shown in this paper to be dependent upon laser fluences and it proved that the ablation at lower fluence led to the creation of smaller nanoparticles, smaller aggregates of nanoparticles, and a lower concentration of nanoparticles in contrast an increase of fluence leads to the formation of larger nanoparticles and most of these NPs were aggregated. The produces NPs were characterized by mean of many tests such as UV-visible (UV-Vis.), Atomic Force Microscope (AFM) and Scanning Electron Microscope (SEM).