The invention discloses a method for preparing high-activity nano-zinc oxide. The method comprises the steps of weighing zinc sulfate, placing zinc sulfate in a beaker, adding deionized waster, and conducting stirring at room temperature till complete dissolution; adding potassium carbonate, conducting stirring at room temperature till complete reaction, and conducting centrifugation to obtain white sediment Zn5(CO3)2(OH)6; pouring the sediment into a three-mouth flask, adding dimethylsulfamoyl chloride, triethoxyvinylsilane, hydroxypropyl methacrylate, diethyl (hydroxymethyl)phosphonate and diethylenetriaminepenta(methylenephosphonicacid) sodium salt into the three-mouth flask, and conducting magnetic stirring and vacuumizing; heating mixed liquid in the three-mouth flask and conducting heat insulation; adding absolute ethyl alcohol to the obtained mixture, conducting centrifugation to obtain a sediment, and conducting centrifugation and drying with absolute ethyl alcohol again to obtain a nano-zinc oxide material. The prepared nano-zinc oxide has a large grain size, poor dispersity and small draw ratio, and specific surface area and chemical activity are improved.