Abstract: The molecular characters of deformed coal and undeformed coal from Pingdingshan mine were studied with FTIR and 13 C NMR. The values of hydrocarbon-generation potential (′ A′) and the length of aliphatic chains and branching degree (B) for deformed coal are smaller than those of undeformed coal,and the values of aromatic lipid ra- tio (I) for deformed coal are larger than those of undeformed coal,and condensation degree (DOC) has no obviously change from the change characteristic of FTIR parameters. With the increased of deformation degree,the hydrocarbon- generation potential (′ A′) decreases and condensation degree ( DOC) gradually increase. From the result of 13 C NMR,all kinds of functional groups contributes to the change of aromatic carbon and aliphatic carbon. The main con- trolling factors which makes the difference of deformed coal and undeformed coal for aromatic carbon area are protonat- ed aromatic carbons and aromatic bridgehead carbon ( faH,B ), and its for the aliphatic carbon area are methylene (fb2 ). With the increased of deformation degree,methylene (fb2 ) decreases and protonated aromatic carbons and aro- matic bridgehead carbon (faH,B ) gradually increase. The chemical structure of deformed coal was analyzed by fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (13 C NMR) and the effect of deformed coal on gas outburst was further revealed.