Since modern production system is a highly complicated discrete manufacturing system, it is very difficult to design the production line by traditional means. However, through building model of production system in virtual environment, analyzing and evaluating production system performance based on system simulating technology, the production system’s parameter and configuration can be optimized ahead of production plan to optimize production process and improve production efficiency. In this paper, the main shaft production line simulation model is constructed based on the object oriented discrete system software eM-Plant. The production line throughput, utilization and bottleneck operations are analyzed. Based on this, it can support the configuration of production line optimized. The example verifies that the modeling and simulation technology could be successfully used in manufacturing industry.