A practical oxidizing technique with O_3 has been developed for the passivation of porous silicon(PS).The fundamental role of ozonization may be attributed to the strong oxidizing process of the SiH_x species and dangling bonds(DB).The subsequent 158 d aging effect with the presence of absorbed O_3 molecules is much effective for the oxidizing process.At last we achieve a complete replacement of Si-H_x covered with Si-O_x film and Si-alkyl film.The steady increase of photoluminescence(PL) intensity is due to the increase in barrier's height efficiency and the increase in quantum efficiency for the nano-crystallites.