Abstract: In order to sufficiently and effectively use product model and knowledge in product development, this paper presents a concept named model & knowledge based engineering(MKBE). By realizing the close and intensive integration of product model and engineering knowledge through model-based knowledge definition(MBKD), MKBE is expected to enhance product development. Firstly, the definitions of MKBE and MBKD are declared. Then, a knowledge classification method based on product structure and product development process and the knowledge hierarchical organization method are presented. Finally, the effectiveness of the proposed knowledge classification and organization method is demonstrated with the example of combustion chamber of solid engine. The integration of product model and engineering knowledge provides a technical foundation for MKBE.