A blue luminescent of ZnO:Zn nanocrystal has been successfully prepared by one step spray pyrolysis method without reducing gas atmosphere. Zinc acetate dihydrate aqueous solutions (0.05 M) were atomized by ultrasonic atomizer. The atomizer used an air as carrier gas with 1, 3 and 5 L/min flowrate. The tubular reactor was set at 500, 600 and 700oC. As prepared samples were characterized by means of x-ray diffraction spectroscopy and scanning electron microscope-energy dispersive x-ray spectroscopy (SEM-EDS). The crystal size of as prepared particles calculated by Scherrer’s equation give 10-20 nm. The luminescent properties of as prepared particles were measured using spectrofluorophotometer. The highest photoluminescent intensity of particles irradiated with excited wavelength of 250 nm was obtained from samples prepared using 5 L/min carrier gas with temperature of tubular reactor 700oC. High intensity of blue luminescent was obtained due to oxygen vacancy in ZnO:Zn.