Abstract: The submarine fan reservoir of the Meishan Formation in the Ledong–Lingshui Sag has great resource potential and is one of the key areas for deepwater oil and gas exploration. However, there are currently few studies on the identification of seismic fluids in reservoirs within this region, and the effective detection technology of reservoir fluids is not mature enough. The characteristics of medium and low porosity, low permeability, and complex pore structure in the study area make it difficult to effectively identify fluids by building a fluid factor based on conventional elastic parameters. To address this issue, this paper established a set of fluid identification technology processes and analyzed the main controlling factors of frequency variation in the study area based on the saturated petrophysical model of the Johnson block, which laid a theoretical foundation for fluid identification using the fluid factor based on frequency dispersion factors. A high-precision fluid factor was constructed by extracting the frequency dispersion attributes via the frequency-varying AVO inversion based on the Russell equation, combined with the longitudinal wave velocity difference extracted by the pre-stack inversion of the analytic solution to the wave equation. The application of test data and actual data shows that the fluid factor and well are well matched, and the application effect is good. This set of technical processes has certain reference significance in the fluid identification of the same type of gas reservoir.