The Upper Triassic Xujiahe Formation in Yuanba area, northeastern Sichuan Basin is a typical tight reservoir with poor physical properties, whilst the development of natural fractures improves the reservoir properties. Natural fractures provide the main reservoir spaces and seepage channels thus have an important impact on the natural gas migration, accumulation and high yield. Based on outcrop, core, thin section and image log data, this paper investigates the genetic origin of natural fractures and analyzes the characteristics and main controlling factors of natural fracture development in the study area. Natural fractures are mainly low- and high-angle shear fractures of tectonic origin and oriented NW-SE (300°±10°) and NEE-SWW (70°±5°), with low fracture filling. Fracture development is mainly influenced by structural location, lithology and rock thickness. The favorable sites condusive to high natural gas production have the nose-like structure, within 400 m from the upthrown side of the fault, with vertical fault length between 60-120 m, in the vicinity of the inflection point of the NW fault extension line. Fractures are most developed in medium-fine quartz sandstone and fine-grained feldspar lithic sandstone, with the high-energy, large-scale sand body (high content of quartz and low content of shale) more conducive to fracture development. There is a significant negative correlation between the degree of fracture development and the thickness of the rock layer, where high fracture density and high fracture development are achieved when the rock layer is less than 1 m thick.