Hexagonal ZnO whiskers were prepared by using an optical floating zone furnace. Most of the as-grown whiskers have diameters of about 20-30 µm and lengths of about 2~3 mm. The characteristic peaks of X-ray diffraction (XRD) verify that the as-grown ZnO whiskers have excellent hexagonal wurtzite phase and (001) orientation. The room-temperature photoluminescence spectra show a near-UV emission band located at 380 nm and a green light emission band centered at 515 nm. The threshold of near-UV emission and lasing were observed.