A car body control system, which integrates the aforementioned bus technologies, is proposed in the form of multiple network structure. It consists of CAN bus and UN bus. To facilitate the message interchange among these buses, a CAN/LIN gateway is designed and implemented so that the two sub-networks can be coordinated to build up a bigger and more practical network. In details, the hardware configurations are postulated based on anti-interference metrics. Finally, the reliability and practicality of this approach have been attested.