Effects of quinoline entrainer content, extraction temperature and pressure in fractionation of pitch with supercritical toluene is investigated. Quinoline contents 0, 3, 7, 10%, temperatures 325, 345, 365℃ and pressures 27, 47, 67.2 bar were selected as experimental conditions. The addition of quinoline made the solubility of pitch increase and made changes on extraction selectivity. Furthemore, it was effective on the formation of fusible mesophase pitch. So, it is anticipated that the mesophase pitch could be used as the precursor for the formation of a high-performance pitch-based carbon fiber.