The data of analysis composition among 154 different property coals that are burned and used in pulverized coal boilers by large-scale power stations in China is analyzed and tested. Based on the physical relationship between different coal compositions and the properties of inflammability, stable combustion, new indexes of stable combustion (WR), inflammability YR) are put forward. The core characteristics of the new indexes are as follows：In stable combustion introduces the heat absorption value of moisture , of cokeand heatliberation value of volatile matter , when the coal finesreach the ignition temperature；In inflammability introduces the ratios betweenand; Combining with traditional technologies, the distribution function relation of and is fitted；New methods of image resolution and the boundary value are also given out. The result demonstrates that under the conditions of model,≈55.8%-93.2%. The smaller the value, the stronger the stable combustion is. With the combination of new indexes and traditional technologies, the burning features of different coals canbe more clearly recognized.