This paper describes an innovative systematic approach to factory automation. Northwestern Polytechnical University developed an Enterprise-level Digital fActory and its Simulation Platform, NPU-EDASP that adopted service-oriented architecture methodology to design and develop this software. In particular, it specifies the simulation technology within the NPU-EDASP platform to bridge the gape exits among products and production manufacturing process. In an advanced stage, simulation technology can be applied in the NPU-EDASP to enhance the operative production planning and control. Further, the combination of simulation and optimization techniques will improve and optimize material flow, resource utilization and logistics in production engineering processes. A case study of a model demonstrates that the NPU-EDASP digital factory offers an integrated approach to promote the ability of production engineering.