Abstract: The sequence extraction method was used to analyze the content of alkali metals in different modes of occurrence in Zhundong coal. Most sodium in the coal is water-soluble one, accouting for 59%, while potassium exists mainly in the form of non-soluble aluminosilicates, accounting for 53%. The combustion experiments of Zhundong coal at the temperature ranging from 400 to 950℃ were carried out to study the distribution characteristics of alkali emission between the gas and the solid phase. The results show that the ash yield decreases with the increase in temperature. Sodium releases continuously from coal into the gas phase; However, the content of potassium in the gas phase is lower than that in the solid phase at 400℃, while the content of potassium in gas exceeds that in solid and basically remains the same when the temperature is higher than 500℃. The enrichment of alkali metals in solid occurs and increases with temperature. Moreover, the sodium in the gas phase mainly originates from water-soluble one, and potassium not only releases from soluble ones, but also from non-soluble aluminosilicates. According to the result of XRD, alkali metals will react with SiO₂ and Al₂O₃ to form low-melting-point albite and nepheline.