The ionic liquid precursor tetraethylammonium hydroxide (TEAH) acting as the reactant precursor and the solvent is demonstrated to be effective for synthesis of ZnO particles with controlled morphologies: hollow ZnO rods, flower-like ZnO particles constructed by rods with nanoparticle subunits and porous ZnO microspheres assembled from ZnO nanoplates. The formation mechanism of the synthesized particles is discussed according to the experimental results. Room temperature photoluminescence (PL) spectroscopy is measured to reveal the optical property of the as-obtained products.