Abstract: A new method of measurement for solubility of disperse dyes in supercritical carbon dioxide was designed and the solubility of disperse blue 79 was measured.The effect of temperature and pressure of supercritical carbon dioxide on the solubility of the dye and the relationship between solubility and K/S value has been also investigated.The results of experiments indicate the solubility of C.I.disperse blue 79 decreases with increasing of the temperature and increases when increasing pressure.The K/S value of the polyester fabrics increases when increasing the temperature or the pressure,which have nothing to do with the solubility of the dye.It was observed that C.I.disperse blue 79 partially melted in the condition of(130 ℃、)(22 MPa) and slowly circulation due to high pressure,which lowers the melting point.