As a high speed and redundant bus, FlexRay has broad application prospects. In order to let the FlexRay bus developers to design excellent performance of the FlexRay bus system, including the key point of FlexRay bus design: cable and connector selection, interface circuit design, network technology, through the list of parameters of key selection are discussed in this paper, according to this paper, designers can rapidly develop a bus system that satisfies the FlexRay bus physical layer protocol.