In order to better understand the water and sediment transport characteristics in the arid and semi-arid region of the Loess Plateau under complex geomorphological conditions, a distributed watershed water and sediment process model suitable for the Loess Plateau was constructed based on the vertical mixing production mechanism and kinematic wave equation, coupled with watershed soil erosion and sediment transport modules, and the influence of terraces on water and sediment movement was considered. Measured runoff and sediment data of multiple years of flood events in the Xichuan River basin, a tributary of the Yanhe River in Loess Plateau, were used for calibration and validation of the model. The Nash-Sutcliffe efficiency coefficients of runoff simulation were higher than 0.56, with an average value greater than 0.70. The simulated flood peak shape, peak value, and peak time of the simulated floods were in good agreement with the measured floods. However, the model simulation accuracy of soil erosion and sediment transport was relatively low, with a mean Nash-Sutcliffe efficiency coefficient of 0.79 during the calibration period, but only 0.45 during the verification period. The overall trend of the simulation results was consistent with the measured values, but the peak sediment transport simulation values were lower than the measured values. The model can simulate the flood runoff process in watersheds in the Loess Plateau with relatively high accuracy, however the simulated sediment transport values were lower than the measured values, and this was due to both the error propagation of the production convergence flow module and the insufficient consideration of gravity erosion. Therefore, in the future, the model will consider gravity erosion processes such as landslides and rockfalls to improve simulation accuracy and efficiency, providing an effective tool for simulating watershed water and sediment processes and integrated watershed management.