High-quality ZnO films were grown on c-Al2O3 substrate by atmospheric pressure-metal organic chemical vapor deposition technique, using a method of three-step growth. DEZn and H2O were used as the Zn and O precursors in both the low and high temperature N2 buffers and N2O was used as O precursor in the main ZnO layer. The full width at half maximum (FWHM) of the inclined symmetrical plane (10-12) ω-scan of the ZnO film by double crystal X-ray diffraction method was 350″, indicating the high crystal quality of the ZnO film. Compared with the 10 K low temperature photoluminescence spectra of the H2O-grown ZnO sample, the two-electron satellite peak caused by the hydrogen related neutral donor trapping excition disappeared in that of the N2O-growth ZnO sample. It indicated that hydrogen was not easily introduced into the N2O-growth ZnO film.