Abstract: Azo compounds are very important in organic chemistry. In resent years, some notoworthy studies show that azobenzene derivatives possess very good optic remembering and photoelectric properties, optical switching and image storage by means of azobenzene liquid crystal film.^1,2 We have reported some new methods for the Azo compounds³. In this paper, We describe a new oxidation system KCIO₃/H₂SO₄ catalyzed by FeSO₄ to synthesis diazo compounds (ArN=NCON=NAr) in short time and good yield for the first time.