Regarding the characteristic of the architecture of the sample redundant flight control computer based on CAN (control area network) bus, a bus protocol of internal communication based on time-triggered is presented. The protocol-frame, data-frame, synchronization arithmetic of internal communication are designed. According to the protocol, the communication between the CPU (central processing unit) and each other function unit can be reliable. At the same time, if some node of the network were failure, CPU can check it reliably and then carry through relevant switch logic to realize the redundancy management. The results of the experimentation show that according to the bus protocol designed in this paper, the internal communication of the FCC (flight control computer) was reliable, at the same time, the fault-detect and redundancy management can be realized.