By applying the configuration-bias vaporization method for the simulation of hquid-hquid equilibria based on lattice model,the liquid-liquid equilibria of three ternary systems with the specified molecular parameters（r_1=1,r_2＝4,r_3=8,ε_(12)=0.333,ε_(13)= 0.556,ε_(23)=00）,（r_1＝1,r_2＝4,r_3=l6,ε_(12)＝0.25,ε_(l3)＝0.50,ε_(23)=-0.10）and（r_1＝1,r_2＝4,r_3＝32,ε_(l2)＝0.25,ε_(13)＝0.50,ε_(23)＝-0.10）,respectively,are obtained.Comparisons between the simulation results and those calcu1ated by Flory-Huggins theory,Freed theory and Hu et els model for the Polymer solution are made.It is shown that Flory-Huggins theory have large deviation from simulated results,while Freed theory and Hu et als model gives much better results．