Abstract: This paper presents a systematic thermodynamic calculation about the behavior of potassium,sodium and their chemical compounds in the blast furnace. Based on sample analysis from experimental blast furnace of Bao-Tao st.Co and material balance of wensi blast furance of shan-xi procvince in Smelting potassium orthocluse rocks and the data of sinchan provincical steel Co in smalting Yamansu ore,the formation conditions of potassium and sodiam compounds in the blast fornace cre associateal.