A study was performed on ZnO nanoneedles grown vertically on Si substrates by non-catalytic vapor-phase epitaxy. The surface morphology of as-grown ZnO nanoneedles on Si substrates was investigated using scanning electron microscopy (SEM). It was found that the nanoneedles have high crystallinity and excellent photoluminescence (PL) characteristics. A narrow and strong emission peak was observed at 3.29 eV from the photoluminescence spectra, with a very weak deep-level emission, indicating that the nanoneedles were of high optical quality.