Abstract: The blast furnace gas ash has features of fine particle size and complex composition，and its main ingredients are calcium oxide，hematite，calcite，zinc oxide，carbon with the content of iron，zinc and carbon 27.44%，8.76% and 13.51% respectively.The main zinc-containing is zinc oxide，iron-containing ore is hematite，and carbon mainly exists in the form of coke.In order to determine the appropriate sulfate concentration，solid-liquid ratio and leaching time of sulfuric acid leaching zinc，the 3 factors 3 levels orthogonal test was carried out.The results showed that the concentration of sulfuric acid played an important role in zinc leaching rate，followed by liquid-solid ratio；At the same time，it showed that when the sulfuric acid concentration was 0.6 moL/L，the liquid-solid ratio was 7 mL/g，leaching time was 25 min，the zinc leaching rate reached at 97.03%.

Key words: Blast furnace gas ash, Leaching zinc with sulfuric acid, Orthogonal test