Abstract: A new centralized communication scheduling subsystem based on time division multiplexing (TDM) and a distributed communication scheduling subsystem based on priority to deal with periodic and sporadic data transmission respectively is presented in this paper. The system solves the problem of real-time and determinacy of data transmission and the problem that the data frames with different priorities cannot share the bandwidth equally when the utility of controller area network (CAN) fieldbus is high. This method combines the TDM principle in communication and the bottom protocols properties of CAN. In the case of up to 83% utility of network bandwidth, the real-time transmission of data is ensured. It has been applied and verified in a practical roller kiln monitor and control system.