To acquire the method of business process simulation of architecture, the article introduces the concept, element and function of simulation of architecture, does the research of business process simulation model structure of architecture based on IDEF3(ICAM (Integrated Computer Aided Manufacturing) DEFinition method 3), includes process model, resource model, time model, organization model, junction and link model, presents the steps to analyze the complex system based on the business process simulation method of architecture, the character of the SA(System Architect) tool. The method of article can evaluate system requirements, rationality of campaigning rule expediently, and has theoretical guidance significance to the research of business process simulation.