The modified method of improving the interface adsorbing of natural manganic ore by hy-drazine hydrate was studied. The result shows that the adsorbing of natural manganic ore to methyl orange was improved markedly after it was modified by hydrazine hydrate,and it was found the adsorbing was in-fluenced by concentration of sulfuric acid,dosage of hydrazine hydrate,dosage of potassium permanganate, and temperature of the modified reaction,etc. The adsorption pH curve has shown `reverse S-type'. Under the condition of pH <2. 4, the methyl orange can be strongly removed from wastewater by the modified manganic ore. The adsorption isotherm was in keeping with Langmuir-type. When the temperature was 20 ℃, the adsorption saturation was 776. 5 mg/g.