For the change of market condition such as increase of demand and new selling price, an optimal retrofit method is proposed through adding new equipments to existing multiproduct batch plant. Until now, the optimum volume and the appropriate position of adding equipments are solved using mixed integer nonlinear program. In this paper, a heuristic procedure is presented which first determines the positions of adding equipments. Then a nonlinear programming is formulated to obtain their optimum sizes. The effecti-veness of this method is verified by solving several literature problems.