The conventional FlexRay communication unit has complex wiring and low reliability, in order to improve the network rate, reliability and flexibility, this paper adopts the method of hardware and software combination. This article designed the FlexRay bus communication unit with the background of high-performance MC9S12XF microcontroller. The hardware structure and software design processes of the FlexRay communication unit are proposed respectively. In this paper, certain scientific basis for FlexRay communication exploitation is provided for the circuit with the characteristics of real-time, simple hardware design and high reliability.