Composition of product was numerically simulated as function of reflux ratio and feed quality in the continuous distillation for the both of steady state and dynamic state. Answer for process model were found using MATLAB by virtue of Newton method for simultaneous equation and the Runge-Kutta method for simultaneous differential method. For the both of steady state and dynamic state with the change of step input, it was found that purity of product was increased with higher recycle ratio and lower feed quality.