Abstract: In order to reveal a gas occurrence law of No.21 seam in Jiaozuo Mining Area,a gas geological theory and regional tectonic evolution were applied to study the tectonic evolution of the fault zone in front of Taihang Mountain and the control role to the seam gas formation,migration and preservation in Jiaozuo Mining Area. The r esults showed that the thermal metamorphism of the regional magma caused No.21 seam to be high metamorphism anthracite and great gas was formed. The lifting role 0 f the Late Jurassic crust made the gas dissipation highly. The sedimentation role of the new tectonic period and the hydrogeological condition would be favorable to the gas preservation and were the main cause of the high gas content in the mining area. After several tectonic evolution periods,the EW directional fault could have good preserva tion role to the gas,the new tectonic period had a short period releasing of the gas and the gas in the two sides with a scope of 250 m of the fault was reduced. The NE dire ctional fault was widely developed,was reconstructed with several extrusions and shearing tectonic role and would be favorable to the gas preservation and tectonic coal fo rmation.