實驗與模擬結果顯示，在相同的進料壓力下，錐長150mm的水旋風分離器分級效率最高；在粒子追蹤部分，水旋風分離器的錐長越長，越能提高粒子往底流的機率，代表錐長越長分離效果越好。 This study used 45 mm diameter hydrocyclone to experiment which with cone length 85 mm, 110 mm, 150 mm. The black silicon carbide as experimental particulates. Fluent, a simulation program, to carry out the process simulation. Furthermore, we discussed the separation of the hydrocyclone when we changed the cone length, also, we compared the performance as before. Based on experimental results, to simulate and analyze in multiphase VOF model and the LES turbulence model. At the same time, we set discrete phase model to analyze the motivation of particulates for observing the efficiency of classification. The experimental and simulated results show that in the same inlet pressure, cone length 150mm in hydrocyclone separation is better than cone length 85mm and 110mm. In particle track section, hydrocyclone with cone length 150mm,it can increase the chance that particles move to underflow. Its means the cone length getting longer, the separation is better.