Abstract: The three-component alcohol batch distillation process was simulated by the Thomas method based on ASOG phase equilibrium theory.The distortion of the simulation results was effectively avoided by using an accurate verifying method.Experimental results showed that the mathematical model is accurate and the numerical method is reliable.The objective function for economic benefits per time unit was proposed，and the effects of reflux ratio and theoretical plate number on economic benefits per time unit were discussed.In conclusion the optimal reflux ratio and the optimal theoretical plate number were 5.5 and 20 respectively under the given condition.