Abstract: With the Shan’xi Qinshui Basin as a case，the geological mechanisms of structures controlling the occurrence of coalbed gas reservoirs with high-permeability were studied through a comprehensive analysis of modem tectonic stress field and curvature．The results showed that the testing well permeability of the major lower Permian Shan ’xi Formation coal reservoirs is positively and exponentially correlated to the main maximum stress difference of modem tectonic stress field an d the structural fissures in the coal reservoirs occur mostly in the zones with the structural curvature more than 0.1×10-4 /m．The zones matched high curvature to high main stress difference in the central and southern basin extend in the NNW strike，where the coal reservoir permeability is relatively high．The tectonic stress affects coal reservoir substantially through controlling the open-close degree of the fissures in coal reservoir．