Abstract: Detailed observations and statistics of tectonic fractures in outcrops,drilling cores and thin sections have been made and the basic characteristics, mechanics and origin of tectonic fractures in reservoirs of the Triassic Yanchang Formation in the Zhenyuan-Jingchuan area have been analyzed.According to the actual conditions of tectonic fractures in the target strata in the Zhenyuan-Jingchuan area and on the basis of finite element simulation,the authors have quantitatively predicted and evaluated the distribution and development degree of the tectonic fractures by using the rock breaking method,which may be used as a reference for evaluation of a favorable target area in petroleum exploration in the Zhenyuan-Jingchuan area.