Due to the growing number of requirements and the introduction of new technologies, current trends indicate that more disciplines have been involved into the system design. The design of such multidisciplinary systems, especially during the detailed design phase, requires designers and expertise from different disciplines. Therefore, the research question about how to achieve an integrated design for multidisciplinary systems has attracted the attention from both academia and industry. In order to achieve such integrated design for multidisciplinary systems, more and more researchers focus on the interface of multidisciplinary systems because the interface plays a quite significant role to guarantee the components defined by the designers of different disciplines integrate correctly and to eventually help them to achieve the integrated design. This article presents an interface knowledge base to manage the design data and rules related to the interfaces. A knowledge-based engineering approach is then proposed. By applying the knowledge-based engineering approach, a synergistic integration of the discipline-specific components can be realised; however, the unnecessary iterations can be avoided so that a concurrent design process during the detailed design phase can be achieved. This knowledge-based engineering approach is demonstrated by the case studies based on a partial discharge detection system and a belt conveyor system.