Mesophase(Nematic liquid crystal, anisotropic) pitches which have different amounts of meso-phase were prepared from coal tar pitch, and separated into mesophase and isotropic phase by a high-tempera-ture centrifugal method. Phase separation of mesophase pitch and formation of new mesophase on the influ-ence of centrifugal method. Phase separation of mesophase pitch and formation of new mesophase on the influ-ence of centrifugal acceleration were investigated. Densities of both mesophase and isotropic phase were measured. Mesophase pitch was easily separated into mesophase and isotropic phase by the high-temperature centrifugal method. But in case that the mesophase content in pitch is over about 82vol%, centrifugal separa-tion was very difficult because of very small density difference between mesophase and isotropic phase. The rate of mesophase formation was increased by centrifugal acceleration and C/H atomic ratio of mesophase separated under higher centrifugal accelertion was increased. The density of mesophase was remained con-stant at 1.385g/cm³, and that of isotropic phase was increased from 1.300g/cm³ to 1.370g/cm³(separated from 57vol% mesophase pitch)with increaing of heat treatment time.