Based on the analysis of product-based and data-centric methodology for development of architectures, core entity-based methodology for development of integrated architecture is proposed. Integrated architecture is described, architecture core entity is defined, and the relationships between core entities are analyzed. Then, the paper comments on basic principles, analyses its workflow steps and presents the workflow steps of architecture products development by System Architect. The results show that not only the relationship and consistency of the architecture data is emphasized, but also the importance and effect of operational activity and system function is highlighted.