The invention discloses a preparation method of an antibacterial hydrophobic ZnO nanorod. The preparation method comprises the following steps: (1) mechanical polishing of titanium pieces: the titanium pieces are polished in sequence to obtain smooth surfaces; and the polished titanium pieces are positioned in acetone, anhydrous ethanol and de-ionized water in sequence for respective ultrasonic cleaning by 15 minutes, and are naturally dried at room temperature for future use; (2) preparation of a ZnO seed layer: the polished titanium pieces obtained in the step (1) are used as a substrate to plate the uniform ZnO seed layer; and (3) preparation of a ZnO nanorod: the substrate coated with the ZnO seed layer in the step (2) is reversely suspended in water solution of zinc nitrate hexahydrate and hexamethylenetetramine for hydrothermal reaction and natural cooling; and after the substrate is taken out for cleaning by the de-ionized water, the substrate is dried to form the ZnO nanorod. The ZnO nanorod has the advantages of: better antibacterial efects, no need of high-temperature heating, no harmful gas, economy, environmental protection, broad spectrum, high efficiency, long bacteria resistance and a certain biological compatibility.