Hyperconcentrated sediment-laden floods usually occur in the Lower Yellow River (LYR) during rainy seasons. During these floods, extreme high water levels and strong channel scour in local reaches often occur, which may cause the damage to the safety of flood control engineering. Therefore, it is necessary to adopt one-dimensional (1-D) morphodynamic models to simulate hyperconcentrated floods and corresponding channel evolution in the LYR. In the current study, a 1-D coupled morphodynamic model has been developed to simulate hyperconcentrated floods. In this model, the standard Saint-Venant equations are modified, and the sediment concentration and bed evolution terms are directly included in the modified equations. These equations are used together with the non-equilibrium transport equation for graded sediments and the equation of bed evolution. Since the governing equations are solved jointly, the hydrodynamic, sediment transport and morphological parameters are obtained simultaneously. The model was first applied to simulate a hyperconcentrated flood event occurring in 1977 in the LYR, with the field measured data of discharge, total and graded sediment concentrations at hydrometric sections being used to calibrate the model. It was then used to predict the discharge and sediment concentration hydrographs in the 2004 flood event, again using the field measured data to verify the model. Close agreement was obtained between the model predictions based on the coupled solution and the observed data.