Abstract: Most of the tight sandstone and carbonate rock gas reservoirs are mainly low-porosity and low-permeability reservoirs with a variety of complex porous genesis and types. The porosity and permeability have an important influence on the seismic elastic modulus and velocity, making gas detection very difficult. To focus on the low porosity and low permeability complex pore media, the integrated evaluation of porous structure and seismic rock physical analysis can be used to evaluate how the complexity of porous structure and heterogeneity of porous fluid distribution influence seismic wave velocity, thus unveiling the law that seismic wave velocity changes with the physical properties and fluid properties. The White model is modified to represents the relationship between compressional wave velocity and gas saturation and establish the quantitative prediction template of gas saturation of low-porosity and low-permeability reservoir in order to promote seismic quantitative interpretation technological research and development. Good results were achieved when the research results were used to make seismic quantitative prediction of gas saturation in the tight sandstone gas reservoir of Xujiahe Formation in Sichuan Basin, SW China.