The recent gas exploration in West China demonstrated that formation conditions of tight‐sandstone gas are distinct from typical ones in North America. One remarkable difference is that complicated tectonic conditions in the foreland basin of West China, especially the Himalayan tectonic movement, resulted in widely developed fractures in tight‐sand reservoirs. Thus, this work employed dual media to characterize tight‐sand reservoir system and explain the impact of dual media on tight‐sand gas reservoir by: (a) describing the feature of fractures and properties of Yinan 2 tight‐sand reservoir; (b) characterizing dual media with mercury intrusion porosimetry, full diameter and conventional core analysis; (c) discussing gas charging and accumulating in dual media based on the difference between dual media and tight‐sand rocks. Observation from cores, FMI images and thin sections suggested that macro‐ and micro‐fractures are widely distributed in Lower Jurassic Ahe Formation (J1a) tight sandstones, with dip angle of 70° to 80°. These fractures are strongly scale‐dependent with length of several centimetres to a few tens of centimetres and apertures of several hundreds to several thousands of microns. J1a tight‐sand reservoir is characterized by poor porosity, with an average value of 7.7%, whereas measured permeability varies from 0.01–100 mD. Intrusion and extrusion curves of dual media and tight‐sand rocks are significantly different from each other, while displacement pressure and medium saturation pressure of dual media are lower than tight‐sand rocks. Importantly, maximum pore throats of dual media are 1.75–32.22 times larger than juxtaposed tight‐sand rocks. The ratio of permeability between dual media and tight sandstone is up to 1,000, whereas the ratio of porosities only ranges from 1 to 1.5. Thus, dual media in tight‐sand reservoir represents high permeability system and matrix pores are primarily storage system. The impact of dual media on tight‐sand gas reservoir involves its position, temporal coupling of gas charging and growth. In terms of fracture growth prior to gas charge, multi‐force can work together as a driving force, and fractures as a flow system and matrix pores as a storage system linked by fractures; buoyancy is the primary driving force in fractures. In terms of gas charge prior to fracture growth, dual media can also exert a positive impact on gas charging when occurring in the inner part of tight‐sand reservoir defined by the critical throat threshold. However, dual media can also destroy the “inverted gas–water” and shrink tight‐sand gas reservoir when occurring at the original critical throat threshold.