Siltation caused the reservoir water level elevation, which occupied the regulation storage capacity and resulted in the loss of the reservoir storage capacity. Because of the abrasion of the hydroturbine caused by the harmful particles, the operation efficiency of the hydroturbine dropped, the output and annual power generation decreased, and the maintenance interval was shortened while the cost increased. Taking a hydropower station in Yunnan Province as an example, the unsteady one-dimensional model is used to simulate the sediment pattern, sediment erosion and deposition, and sediment concentration in the reservoir area. The results show that the reservoir sedimentation patterns is delta sedimentation, and the sediment deposition has great effect on regulation storage capacity. The sediment through the hydroturbine has small amount of sand and fine sediment gradation, and the sediment also has small impact on the hydroturbine. The numerical simulation of sedimentation is consistent with the measured data, so it is feasible to use the unsteady one-dimensional model for numerical simulation of the sediment deposition and effectively solve the problem of numerical simulation of the sediment deposition in Yunnan Province.