Abstract: To acquire information on the distribution and properties of seafloor sediments, the coupling relationship of sediment parameters in the seafloor high-frequency scattering model is analyzed for sediment classification. Initially, based on the Sternlicht high-frequency scattering model, the time-domain echo pressure envelope from single-beam echosounder is simulated. Then, the coupling relationship of sediment parameters (index of impedance, spectrum intensity, spectrum index and volume scattering coefficient) is analyzed for different seafloor sediment types in shallow water. Finally, the fitting line slope of the coupling fringe is extracted from the experimental data conducted in Qingdao offshore to classify seafloor sediment types. The simulation results based on the high-frequency scattering model show that three sediment parameters (index of impedance, spectrum intensity, and spectrum index) are sensitive and coupled to each other. They jointly affect the intensity of the time-domain echo pressure envelope, which is directly related to different sediment types. Therefore, different sediment types can be classified by the coupling relationship of acoustic characteristic parameters. The experimental results show that the soft and hard sediment types can be effectively distinguished by the fitting line slope of the coupling fringe.