Abstract: A simulation framework of scheduling re-entrant lines with Neuro-Dynamic Programming(NDP) is presented.The state set is constructed based on the characteristics of re-entrant lines,and the scheduling problem is described as the corresponding Markov decision process.Proper performance index is selected,and each scheduling decision is produced and improved in simulation with NDP.An example is given to illustrate the validity of the method.The comparison of three scheduling policies indicates the superiority of NDP in scheduling re-entrant lines.The presented simulation framework can be extended to scheduling of other kinds of production systems.