The Electro-chemistry process to produce Fenton reagents has been described. The in situ oxidation of dyes, acid chrome and alizarin red(Fenton reagents) with electrogenerated hydroxyl radicals was investigated. The I-Vcyclic voltammograms were measured. The redox peaks of the dyes were not observed in the treated dye solutions instead of a couple of O2/H2O2 redox peaks. The IR results indicate that acid chrome dye was decomposed into naphthylamine and phenol aminophenol sulfonic acid. The degradation and the decolorization of the dyes were comfirmed by the visible spectrum and the chemical analysis. The CODcr removing rate was close to 80%.