Abstarct: combustion have been developed and successfully used for the preparation of pure spinel powders. Among these processes, sol-gel process has been widely used because its first step is in solution which allowed molecular mixing of precursors. On the other hand, hydrothermal process has been used for preparation of mextal oxides at lower temperatures in comparison with solid state and other preparation methods. In this research we have combined these two powerful processes and used hydrothermal-assisted sol-gel process for the preparation of zinc aluminate nano-particles. Aluminum iso-propoxide as aluminum precursor and zinc acetylacetonate and zinc chloride as zinc precursors mixed in stoichiometric ratio with appropriate concentration in desired solvents. The mixtures were then hydrolyzed in a stainless steel reactor at different temperatures. The produced gels dried at 100ºC overnight and calcined at 700ºC for 3 hours. Produced powders were characterized by IR, PXRD, SEM and TG/DSC. It was concluded that ZnCl2 as zinc precursor, polar protic solvents such as alcohols and hydrothermal process at 50ºC were more appropriate for the preparation of pure single phase zinc aluminate with particle size of 10-25 nm.