The separation of tertiary butanol (TB) from aqueous solution was studied by salting-out effect for practical application. The final concentration of alcohol can be concentrated into 96% from its original 60%. More than 20 salts were experimented upon to compare their salting-out capacities. According to the concentration target, potassium fluoride (KF) was chosen as a salting-out agent for TB aqueous solution. The liquid-liquid equilibrium data of TB-H2O-KF system and the relationship between the amount of KF and the concentration of TB at different temperatures have been measured and reported. The method of salt addition has been optimized by experiments. KF liquor can be used as salting-out agent. A mathematical model was set up by Pitzer theory and Wilson equation. The Wilson parameters and the Pitzer parameters were obtained by regression.