Abstract: The dense sandstone gas reservoirs in the narrow channel of the Zhongjiang gas field are the sub-agrays of the “deep source shallow gathering” with faults as the migration channels. The effectiveness of the fault, that is, the "break-sand" configuration relationship directly affects the gas-filling degree of the gas reservoir. The three-dimensional seismic interpretation method of "well-seismic combination" is used to describe the basic characteristics of the fault, the internal structure of the fault, the shape of the section, etc., combined with the results of the evolution of the fault structure to evaluate the effectiveness of the fault. By analyzing the "break-sand-source" matching pattern, the influence of the tectonic evolution of the fault and the configuration relationship with the sand body on the accumulation of gas reservoirs is studied. The study shows that the Shaximiao Formation of the Jurassic in the Zhongjiang gas field is a “narrow” channel tight sandstone gas reservoir with deep-source shallow-collected and broken sand-conducting, and the gas reservoir is a low-porosity and low-permeability pore-type reservoir. By analyzing the configuration relationship between the accumulation period and the current "break-sand", it is determined that the "break-sand" configuration mode is divided into three categories, and the corresponding target level evaluation criteria are established. The results provide an idea for the evaluation of the fault validity of the tight sandstone gas reservoirs of the narrow channel of the Shaximiao Formation gas reservoir in the Zhongjiang gas field.