ZnO with spindle shape was synthesized by ultrasonic-assisted reflux method. The micrograph and structure of ZnO sample were charactered by SEM, TEM and XRD.The results show that basic content of solution, ultrasonic treatment and the mass of diethanolamine play an important role on the formation of ZnO with spindle shape. The growth mechanism of ZnO with spindle shape was discussed. Furthermore, the optical properties of ZnO with spindle shape were revealed by UV-Vis and fluorescence spectroscopy.