Abstract: Structural characteristics of different chemical components of Yimin lignite were analyzed by using Fourier transform infrared spectroscopy (FTIR),the curve-fitting analysis was employed to characterize the infrared spectrum different chemical components of Yimin lignite by using origin 7. 5 software,and the FTIR structure parameters were also calculated. The results were obtained as following:for the demineralized coal,comparing with the raw coal,the car- boxyl vibration peak became sharp,two adjacent hydrogen increased and four adjacent hydrogen decreased,aliphatic CH2 vibration decreased and aliphatic CH3 vibration increased,FTIR structural parameters I1 ,I2 and A all increased, which demonstrated its good hydrocarbon generation capacity;for humic acid and asphaltene,they have more carboxyl- ic acid and OH-π hydrogen bond,more two adjacent hydrogen and five adjacent hydrogen,more aliphatic CH vibra- tion and less CH2 vibration,the humic acid has the most aliphatic hydrogen,indicating that the aliphatic hydrocarbons in humic acid and asphaltene is short and high branched;for the residue,it has more aromatic C C vibration,and the aliphatic chain is long and less branched.