Abstract：In this study， emission factors （EFs） of PM2.5， organic carbon （OC）， elemental carbon （EC） and polycyclic aromatic hydrocarbons （PAHs） were determined from simulated combustion of 7 different raw coals with different geological maturity in a combustion chamber equipped with a dilution sampling system. The relationship between raw coal properties and EFs were analyzed， and the diagnostic ratios of PAHs from raw coals were calculated. The results showed that the EFs of PM2.5， OC， EC and PAHs from anthracite （the highest geological maturity） were the lowest， which were （0.28±0.07）， （0.07±0.04）， （0.003±0） g·kg-1 and （1.15±0.84） mg·kg-1， respectively. With the decrease of geological maturity， the EFs showed a fluctuating upward trend. In detail， the EFs of PM2.5， OC and PAHs of bituminous coal with medium geological maturity （28.08% volatile matter） were the highest， with EFs of （5.17±0.33）， （2.50±0.93） g·kg-1， and （240.39±180.55） mg·kg-1， respectively， which were 1 to 2 orders of magnitude higher than those from anthracite. Correlation analysis showed that the volatile content of coal was strongly positive correlated with the EFs of PM2.5， TC， OC and EC. Among the diagnostic ratios of PAHs emitted from coal combustion， the ratios of Ant/ （Ant+Phe）， BaA/ （BaA+Chr） and IncdP/ （IncdP+BghiP） were discrete， which should be cautiously used in source apportionment. In comparison， the values of Fla/ （Fla+Pyr） and BbF/ （BbF+BkF） were relatively concentrated and stable， which can be used as the tracers to distinguishing different coal combustion emissions. Fla/ （Fla+Pyr） and BbF/ （BbF+BkF） showed a downward trend with the decrease of coal geological maturity， and had a significant negative correlation with volatile matter， with correlation coefficients of -0.78 （p<0.05） and -0.94 （p<0.01）， respectively. This study revealed that the geological maturity of coal strongly affects the formation of isomers in PAHs， and the coals with high maturity （low volatiles） tend to form Fla and BbF during combustion. This phenomenon provides more powerful evidence to distinguish emissions between bituminous coal and anthracite coal combustion.