Using argon as the transporting gas, freestanding macroscopic ZnOstrands have been synthesized by evaporating metal zinc pellets at900 °C in a quartz tube. Scanning electron microscopy images show that the macroscopic ZnOstrands are self-twined by ZnO nanowires with a diameter in the range of 20–30 nm. A ZnOstrand synthesized under larger argon flux contains more oxygen vacancy, which willresult in a stronger green emission at 2.43 eV. Under illumination with a power of10 W, the photosensitivity of the ZnO strand is found to be about 800 at thebias voltage of 20 V. It is also experimentally demonstrated that the recoverytime of the ZnO strand is relatively long due to the dominating surface process.