A method for improving the antibacterial property of a tetrapod-like zinc oxide whisker comprises the steps of A. adding the tetrapod-like zinc oxide whisker taking the shape of white powder in an aqueous solution of potassium sodium tartrate to form paste or suspension and stirring for 10-30 minutes, wherein the mole ratio of the potassium sodium tartrate to the tetrapod-like zinc oxide whisker is (0.1-1):100; then under the state of stirring, slowly adding an aqueous solution of copper chloride with the same molar weight as the potassium sodium tartrate; later continuing stirring for 30-60 minutes; at last, conducting filtering, washing and drying, thus obtaining tetrapod-like zinc oxide whisker compound powder with nanometer cupric tartrate in-situ deposited on the surface; and B. increasing the temperature of the compound powder to 270-300 DEG C, keeping the temperature for 15-60 minutes, and conducting cooling to room temperature, thus obtaining the tetrapod-like zinc oxide whisker with strong antibacterial property. The powder obtained by the method has strong antibacterial capability, sterilizing rate of 98.5%-99.9%, low cost, does not change color when in use and is easy to popularize.