Abstract: Fe/ diatomite catalyst was prepared using diatomite as the carrier and ferric nitrate as the Fesource .'The treatment effect and influencing factows of the heterogeneous Fenton system composed of Fe/diatomnite catalyst and H,0, on methylene blue dye wastewiater wre studied. The experimental resultsshowed that the heterogeneous Fenton system compsed by Fe/ diatomite catalyst and H,0。 had significantdegradation effect on methylene blue in dye wastewater. Under the conditions of catalyst dosage of1.6 g/L，H,0, dosage of 0.2 molL.，solution pH value of 3.0 , reaction temperature of 30 C and reac-tion time of 60 mimutes , the decolorization rate of methylene blue could reach 92.5%.

Key words: diatomite, heterogeneous Fenton, methylene blue , calalytic degradation