The wet-laid forming system is one of nonwoven manufacturing techniques to produce ideally isotropic webs from the specialty fibers having brittle and high strength properties such as glass, carbon and oxidized carbon fibers. To make the high performance wet-laid nonwovens, the fibers have to be easily dispersed in water with no defects (i. e., log, rope, dumbbell). In this study, we have theoretically suggested the mechanism of fiber dispersion behavior in water under the assumption of dispersion kinetics theory. And then we have experimentally evaluated the effects of processing factors, such as aspect ratio, fiber consistency, dispersing agent and mixing time, on the visibly perceived dispersion of the carbon and oxidized carbon fibers in water. As the results, the water dispersion of carbon fibers is poor with increasing aspect ratio and fiber content, while it does not show any difference when mixing time is increased. The nonionic surfactants on the dispersion of fibers in water are remarkably effective, however the anionic surfactants are not as evident as the nonionic ones. The oxidized carbon fibers are more uniformly dispersed than the carbon fibers in all processing conditions.