It is very complex to choose the minimum hazard particle size of sediment. There has been no breakthrough progress, and many problems still need further studies. This paper first analyzed the main factors of turbine wear comprehensive system, showing that the current domestic sediment minimum hazard particle size selection method is not accurate. In addition to the supplementary design head, sediment content, water flow velocity, of water and sediment relative factor comprehensive factor correction based on minimum hazard particle size through various sediment desilting basin investment and turbine wear maintenance analysis, the minimum hazard particle size was selected, and this method was applied in the Mazi River Hydropower Station. The results show that the smaller the minimum hazardparticle size, the investment greater, and the turbine wear maintenance smaller. When the sediment particle size is 0.25 mm, the desilting basin investment and wear maintenance expenses was the least. Therefore, settling basin sediment minimum hazard particle size of 0.25 mm was reasonable, and comprehensive factors of filling sand replenishment factor correction selection the minimum diameter of sediment hazard method is feasible.