Abstract: In recent years,a large amount of Australian coal has been imported to coal-fired power plants in China,which can be classified by high-moisture Australian coal and low-moisture Australian coal according to the coal characteristics.The coal quality index and combustion characteristic of high-moisture Australian coal is similar to that of the Shenhun coal in China,while the characteristic of low-moisture Australian coal is similar to that of the Youhun coal in China.It is usually found that the carbon content of fly ash increases and the boiler efficiency decreases when the low-moisture Australian coal is used in coal-fired boilers.In order to explore the key reasons for the poor burnout characteristics of low-moisture Australian coal and their discrimination methods,and provide guidance for the reasonable use of low-moisture Australian coal and the optimization of combustion adjustment,the low-moisture Australian coal and Youhun coal were sampled for research.By means of coal quality index analysis,grindability analysis,thermal analysis,porosity analysis and Malvine particle size analysis,the differences of coal quality index,combustion characteristics,porosity and particle size distribution between Australian coal and premium coal blends were studied.The results show that the coal characteristics are similar between the two coal samples,but the oxygen content of low-moisture Australian coal is lower than that of Youhun coal,which indicates that the coalification level of Australian coal is higher than that of Youhun coal. The Hardgrove grind ability index( HGI) or the oxygen content can be used to determine the burnout characteristics of Australian coal since the HGI decreases when the oxygen content increases.Besides,the defined burnout index C700 of thermal analysis is effective to describe the practical combustion characteristics too. The larger pulverized coal size under the same milling conditions is determined to be the main reason why the low-moisture Australian coal is hard to burn out.