Abstract: Coal gangue is a kind of solid waste with enormous emissions. And the main composition is silicon, aluminum and iron. Leaching behavior differences of aluminum, iron and silicon components from coal gangue in Gujiao Dongqu Mining Area were studied using sulfuric acid as leaching agent. The results showed that the leaching differences between aluminum, iron and silicon components in coal gangue were very obvious. Under the optimal conditions of sulfuric concentration of 7.5mol/L, liquid-to-solid ratio of 4:1、120℃for 150min，the leaching ratios of TFe, Al2O3 and SiO2 are 98.31%、97.19% and 15.88% respectively. And Leaching rate difference between TFe and SiO2、Al2O3 and SiO2 are 82.43%、81.31% respectively. Obviously, the sulfuric leaching can realize clean separation between TFe, Al2O3 and SiO2 in coal gangue. TFe, Al2O3 component was concentered in the leachate, SiO2 component was enriched in the leaching residue. The Al and Fe element content in eventual leachate were 10.2 g/L and 3.4 g/L respectively and the pH<3. The leaching residue with SiO2 content as high as 90.22% was received synchronously