Because lack of reasonable logistics line layout and production strategy for the construction of military production lines, it is impossible to evaluate the advantages and disadvantages of production system quantitatively. For solving this problem, introduce a multilevel simulation modeling method for production line based on Em-Plant. Set up modular and multilevel nested modeling units including parts source, machining center, stereo library and charging area, on this basis, logistics control and scheduling strategy is designed and verified by simulation model. The results show that the method can achieve the uniformity of easy use and flexibility of modeling. Before the actual production, the production system is quickly laid out and rationally planned. It has been successfully applied to the production line of certain type ammunition parts production line.