Abstract: The reverberation is one of the main interferences for active sonar system, so the analysis of spatial correlation characteristics for underwater reverberation is the basis of the anti-reverberation technology. Based on the spatial cor-relation characteristics of reverberation, the definition of the spatial correlation radius of seafloor reverberation is ex-plained in theory, and the variations of the spatial correlation radius and the reverberation intensity with different seaf-loor sediments are studied by use of experimental data. Under non-uniform seafloor sediments, the results show that the spatial correlation radius of seafloor reverberation decreases as the scattering particle size increases, and the reverbera-tion intensity increases as the seafloor sediment hardens.