The invention relates to a rapid and simple preparation method of nano-zinc oxide, which takes zinc chloride and sodium hydroxide as raw materials, takes the sodium hydroxide as a strong alkaline regulator, takes oleic acid as a precipitant, takes anhydrous ethanol as a solvent and a centrifugal separating agent, takes deionized water as the solvent and a cleaning agent and takes argon as protective gas. The rapid and simple preparation method comprises the steps of firstly preparing zinc chloride and sodium hydroxide water solution, then mixing with the oleic acid and the anhydrous ethanol for forming solution, carrying out chemical reaction and grain growth under the state of 20 DEG C, carrying out high-speed centrifugal separation, washing and vacuum drying, and finally preparing the white, granular, petal-shaped and single crystal nano-zinc oxide. The preparation method is rapid and simple and can be completed within 4-5 hours without the need of heating, the product has regular and clear appearance, the diameter of single crystal is 2-4mu m, the thickness of single flake is 4-5nm, the chemical and physical performances are stable, the prepration cost is low, the yield can be as high as 92.5%, the product has high purity which can achieve 99.7%, so that the preparation method is the ideal rapid and simple preparation method of the nano-zinc oxide.