Millimeter-sized C60 single crystals were grown by the vacuum sublimation of the purified C60 powder in a sealed vacuum quartz tube. C60 single crystals, up to size of 0.5mm×0.6mm×l.0mm and free from solvent or C70, had excellent faces. X-ray diffraction, electron diffraction and Raman spectra measurement were carried out to determine the room-temperature structure of C60 single crystals. The experimental results show that the temperature T1 of the hot end of tube, the temperature T2 of the cold end of tube and the temperature gradient ΔT= T2- T1 are the primary factors for preparation of large C60 single crystals. The above growth conditions were discussed in detail.