Abstract: Fourier Transform Infrared Spectroscopy (FTIR) was applied in studying the stress effect of compositions of coal macromolecular structure in different deformation environment tectonic coals in Hancheng Mining Area. The 2nd derivative was solved by Peak Fit to determine the peak center of various functional groups and obtain the relative amounts of them,respectively. The results show the coal macromolecular has a response to the stress. The coal marco- molecular is propitious to the transform of the aromatic hydrogen in chemical environment. In middle and higher rank bituminous coals,condensation reaction takes place to improve the degree of aromatic index. The aliphatic chain is eas- ily abscised and decomposed into low weight molecular in strong brittle deformation,while it is condensed into aromatic rings in strong ductile deformation so as to improve the condensation and increase the absorbance of skeletal vibration of aromatic rings under strong tectonic deformation. The stress effect is different in various deformation environments, while the evolutionary direction is the same.