Abstract: In order to study the characteristics of fractures in the tight sandstone reservoirs and their influences on natural gas accumulation, taking Tongnanba structural belt as a case, the paper comprehensively studies the fracture development characteristics in Xujiahe formation in the study area by using the data of core, thin section and FMI logging. According to fracture genesis, the fractures in the tight sandstone reservoir of Xujiahe formation can be classified into 4 types, namely fault-associated fracture, fold-associated fracture, sliding fracture and gravel-associated fracture, among which fault-associated and fold-associated fractures are the main effective fractures. Good correlations among the development of effective fractures, lithology, fault and local structures are found in the study area. Fractures are most developed in the fine sandstones and medium-sized sandstones, and high-curvature anticline and large fracture are favorable conditions for fracture development in the study area. Fracture development in the tight sandstone reservoir of Xujiahe formation was controlled by orogenic activities in the basin margin since Late Jurassic during which the reservoir of Xujiahe formation was densified and the development of fractures improved the reservoir quality and permeability which had important significance for accumulation and high-yield of the gas reservoirs formed at the late stage