The invention provides a fluid identification method and a fluid identification device, wherein the fluid identification method comprises the steps of acquiring a prestack angle gather data volume of a researched area; performing angled stacking on the prestack angle gather data volume seismic data for obtaining an angled-stacked data volume; performing prestack AVO inversion on the angled-stacked data volume for obtaining a longitudinal-wave impedance body and a density body; performing time-frequency decomposition processing on the longitudinal-wave impedance member for obtaining a dividing frequency impedance body; performing inversion operation on the dividing frequency impedance body according to the density body, thereby obtaining a reservoir seismic frequency dispersion attribute on the researched area; and performing fluid identification according to the reservoir seismic frequency dispersion attribute. The fluid identification method and the fluid identification device settle a technical problem of incapability of accurately and effectively performing fluid identification in prior art and realizes a purpose of accurately identifying fluid.