Based on the outcrop and core fractures observation and description,fluid inclusion homogenization temperature of in-filled components in fractures,ESR,acoustic emission technology and the rock mechanics property survey，and combined with development characteristics of microscopic fractures,the development period of fractures and its controlling factors is researched of the Second Member of the Upper Triassic Xujiahe Formation in the Jiulongshan Structure in north of western Sichuan Basin.About 4 stages of fracture development have been identified as late Yinzhi Period, fractures are filled by calcite,in which the fracture fillings homogeneous temperature of inclusions was about 84.4~118.5℃;late Yanshan Period,fractures are filled by quartz,,the homogeneous temperature being 72.1~137.9℃;and the 3rd,4th fracture were developed in early-middle and late Himalayan Period,fractures are filled by quartz and calcite,respectively,and the homogeneous temperature were about 153.3~179.1℃ and 165~174.3℃.The first and the fourth stage is the more stronger tectonic movement，fracture more development.The fracture development has been controlled by tectonic stress intensity and the mechanical property of rock.