To study the erosion reduction effect of a check dam on the landslide, the variation of motion parameters, dynamic parameters, and energy parameters of loess landslide with the rising elevation of the erosion base level were analyzed by Voellmy model based on three-dimensional continuum model. The results showed that the mean velocity, frontal velocity, erosion volume, and total kinetic energy of the landslide masses all increased sharply during the gully-slope motion. As a result, the frontal velocity fluctuated and severely eroded at the slope’s foot, which was extremely destructive. Landslide running time and mean velocity varied within the sigmoidal function distribution range, frontal velocity and landslide moving distance varied within the linear function distribution range, and erosion mass volume and total kinetic energy varied within the exponential function distribution range with the rising elevation of the erosion base level. The motion space and erosion space of the landslide were gradually reduced, which only reduced the landslide velocity to a certain extent, but it could effectively inhibit the erosion effect of the landslide and sharply reduce the mass of eroded materials, thereby effectively reduced the total kinetic energy of the landslide, and reduced the disaster intensity largely with the rising elevation of the erosion base level. The information indicated that the check dam could reduce erosion by the rising elevation of the erosion base level, and the results could be useful for better understanding the erosion reduction mechanisms of a check dam on loess landslide.