Aiming at the influence of high sediment-laden flow on the uplift characteristics of a plunge pool slab, the distribution, magnitude and spectrum characteristics of the uplift force under different sediment concentrations was studied by model test. The results show that the distribution of the uplift force on the plunge pool in sediment-laden flow is similar with that in clean water. For each flow rate, the mean value of the uplift force increases with the increase of the sediment concentration, and basically shows a linear function with a slope between 0. 17 and 0. 22. The standard deviation of the uplift force increases first and then decreases with the increase of sediment concentration, and the standard deviation of the uplift peaks at the critical sediment concentration of 183 kg/m³. The pulsation of the uplift force is in the low frequency range of 0~3 Hz, but compared with the clean water, the frequency band width of the power spectrum increases and the power spectral density in the high frequency domain increases when sediment is added to water. The time integral scale of the flow increases first and then decreases with the increase of sediment concentration.