The SAFT equation of state is applied to the correlation of thermodynamic properties of the binary systems consisting of water-ethanol, water-carbon dioxide and ethanol-carbon dioxide. Based on this, the liquid phase compositions of ternary system are calculated from vapor phase compositions using SAFT equation in the range of 308.15-338.15 K and 10.1-17.0 MPa, in which carbon dioxide acts as a supercritical extraction solvent. The phase equilibria predicted by SAFT agree with the experimental data from literatures accurately.