A cyclone separator is a device that separates solid particles from a fluid using centrifugal force and gravity in its inner chamber. Among cyclone separators, the separator that uses water as a working fluid is called as hydrocyclone separator, which has been developed for the purpose of dehydrating solid mixtures with a proportion of solids floating in liquids greater than 1, such as soil, coal, and cement slurry. In this paper, a hydrocyclone was designed based on the previously proposed design method, and how different the performance is from the targeted value was investigated using the computational fluid dynamics.