Keeping “the Japanese Strength” in digitizing the process of product development is important for the Japanese industry to survive in the intensifying global competition of market. This paper researches about the way of building a comprehensive PLM system based on "the Engineering Process Integrated Architecture (EPIA)" to realize it by taking up actual cases. The system, based on integrated database, consistently integrates the whole process of product planning, development and design, manufacturing preparation, production, purchasing, sales, service and maintenance, and it enables the mutual cooperation of the information of PLM/SCM/CRM.