In this paper has developed a knowledge-based management in flexible manufacturing system that adapts knowledge management concepts into product development where the major objectives were to provide decision support to help economic field, according the utilisation of best-know knowledge, minimise costs, achieve quality assurance and shorten time to product. Product development activities must be structured in such a way that any engineering decisions taken are based on proven knowledge and experience. Any failure to apply knowledge and experience could result in product and process redesign, which would be seen as non-value process and waste of valuable resource. There is a need for a knowledge-based frame work to support flexible manufacturing system development, which includes a knowledge-based system developed from an organisation's knowledge and past experience captured in a database. This process involves the identification, capture, from alisation and presentation of knowledge and its utilisation to support effective decision making within a product development environment.