State space approach is an effective method to mass-exchange network (MEN) synthesis. By decom-posing the network into two interactive parts, a distribution network and a process operator, the synthesis problemcan be formulated into a mixed integer nonlinear programming (MINLP) model. In this article, a generalized statespace model based on typical MEN is established and verified in two cases. A new asymmetrical operator and costindex are also adopted to speed up the solution process. The results demonstrate the efficiency of the proposedapproach.