In this study, the surface chemical functional groups of six different ranked Chinese coals were investigated based on Fourier transform infrared and high-pressure methane adsorption experiments. Four structural parameters calculated by FTIR semi-quantitative method were used to evaluate the chemical characteristics of coals. The impacts of the chemical structural parameters on methane adsorption capacities under different temperature conditions were analyzed systematically. Results show that coal increases its aromaticity with increasing coalification, while aliphatic CH groups in addition to oxygen and hydroxyl groups would be dramatically decreased. With the increasing of vitrinite reflectance, aromaticity and the degree of condensation increases correspondingly, while the chain length present a negative correlations with increasing of vitrinite reflectance. ‘A’ factor peaked in the coal of Ro,max = 1.49% and subsequently decreased in higher rank coals. And, ‘C’ factor shows a saddle type of changing trend for the selected coal rank ranges. There is a positive liner correlation between surface adsorption capacity and aromaticity, and a negative liner correlation between Langmuir pressure and aromaticity. With the degree of condensation increasing, surface adsorption capacity of methane adsorption on the coal shows a rising trend and Langmuir pressure decreases gradually. The effects of chain length on fitting parameters of methane adsorption show that the longer or less branched chain structure is not suitable for methane adsorption.