With the development of scientific and technology, the automotive industries competition is becoming more and tougher. The camshaft production system is an important part of the engine manufacturing. The production line productivity and characteristic are affected by many practical factors of the workshop. It’s a complex discrete manufacturing system somehow. In this paper, the production line model is presented based on Petri net. Then the mapping relationship is established between the Petri net model and the eM-Plant discrete system model. The discrete simulation model of production line is constructed by using eM-plant software. Based on the simulation, the reasonable simulation experimental are carried out with the determined simulation boundary and objectives under the different input conditions such as orders, the working stations' processing time, the working stations’ fault distribution, and the production line layout. The simulation experimental results are discussed on condition that the shifts, equipment operation condition, production line capacity and WIP in detail. These results could provide the theory basis for decision-making of the production plan of the automotive industries.