Abstract: Electron paramagnetic resonance(EPR)experiment has been conducted to study 9 tectonic coal samples and 10 experimental coal samples deformed under high temperature and confining pressure．The results of this study demonstrated that the EPR struetura1 parameters, increasing with the maximum reflectance of vitrinite (Ro, max), are of a characteristic evolutionary pattern．In addition to the high temperature and confining pressure, high strain and high strain rate are beneficial for the increase of spin density(Ng)in medium and high coal ranks．Similarity in the evolution of peak width(△H)h been found between the sample of experimentally deformed and tectonic coals, suggesting that high temperature and confining pressure, as well as low strain rate are favorable for the decrease of H in its stage evolution. Evolution of EPR structural parameters of deformed coals is apparently affected by their original coal ranks. Directional pressure or tectonic stress is of particularly importance in controlling the increase of vitrinite anistropy, structural ordering and orientation of macromolecules of deformed coals. Therefore, Ro, max is also an external reflection of micro-structure evolution of deformed coals and reflects the features of strain environment and stress field. The vitrinite reflectance of tectonic coal is an important indicator for analysis of stress and strain in coalfield structures.