Abstract: A chessboard model of mass exchange networks (CBM-MEN) is proposed. The CBM-MEN has characteristics of compact structure, simple expression, and flexible stream arrangement. A phase of eliminating mass exchanger is added to a random walk algorithm with compulsive evolution. The algorithm is combined with the chessboard model. During optimization process, the mass exchange load is used as an optimization variable. Finally, the simultaneous optimization method is applied to two cases, recovery of copper from liquid effluents of an etching plant and dephenolization of aqueous wastes. The total annual cost of optimized structures is decreased by 5.8‰ and 1.6‰, respectively. It shows that the method has good search domain and search capability.