The mass personalization paradigm requires manufacturing enterprises to adapt to market changes quickly to meet customer demands. It also imposes higher requirements for designing intelligent production lines. Based on the digital twin (DT) technology, a rapid customized design method is proposed for developing new board-type furniture production lines. The DT has the characteristics of interactive virtual-reality mapping and fusion. It could provide design guidance and decision-support services in the design phase, yield the engineering analyzing ability to solve coupled problems, and finally generate the authoritative design scheme of the manufacturing system. A production line design platform is developed based on the DT model, which can parallelize the design process and reduce the design cycle. The parallel control between the physical world and digital space is achieved by establishing the DT network and perceiving the status of the physical equipment. Five key enabling technologies are introduced to provide the theoretical fundamentals for implementing the DT-based manufacturing system design approach. A board-type furniture production line is presented as a case study to verify the effectiveness of the method.