ZnO is one of the most promising materials since it has a high mechanical and thermal stability and wide band gap (3. 37 eV) . In this book we present the successful synthesis of ZnO nanoparticles by different preparation methods such as conventional heating microwave irradiation and sol-gel. Moreover doping ZnO nanoparticles with selective elements Al and Mg to enhance and control the properties of ZnO nanostructures which is crucial for its practical applications will be presented too.