In response to the limitations of existing manufacturing systems and the fast changing environments, reconfigurable manufacturing systems (RMSs) have been proposed as a promising means for companies to manufacture products while meeting individualized customer requirements. In this paper, a simulation based Non dominated Sorting Genetic Algorithm (NSGA-II) approach is proposed to solve the problem of process plans generation for multi-unit single-product type observed in RMS. More specifically, multi-unit macro-level process plans are established in order to schedule different parts/operations on several machines, and where a process plan is associated to each unit in a reconfigurable environment. To demonstrate the applicability of the proposed approach, an illustrative example is presented and the numerical results discussed.