The molecular thermodynamic model for chain-like molecule fluids established by adopting the molecular thermodynamic model for hard-sphere-chain fluids as a reference and a perturbation term contributed by the square--well potential in the previous work have been extended to mixtures.The conformal solution theory

i.e.

the van der Waals one-fluid theory with a temperature independent adjustable binary ineteraction parameter is used to calculate the interaction energy ε/κ between segments of mixtures.Good agreements with experimental data have been obtained for the calculated vapor-liquid equilibria for mixtures of normal fluids with no association.The model can also be used to calculate the binary vapor-liquid equilibria of polymer solutions.