The existence of various CAE engineering softwares improves the simulation efficiency, and also brings out a series of engineering problems at the same time. One of them is how to effectively manage hierarchical simulation process. During the simulation process of mechanical product, the integration of function modules of various engineering software is the key problem to realize simulation task flow. Based on the mechanical simulation features, this dissertation concludes a common mechanical simulation flow, puts forward the concept of Unified Simulation Model, and makes use of Web Services technique in order to make model reused. It has been proved in the design and utilization in an aerospace product that research work in this paper is highly useful in engineering application.