The distributed structure was used to improve the reliability of unmanned aerial vehicle's flight control computer. To the serial input and output unit that has the biggest data traffic, a redundancy management scheme was designed, which can effectively judge the type of fault and handle the fault. To each unit inside the computer, FlexRay bus protocol was designed from three aspects of time scheduling, redundancy management and data transmission in stagger cycle. FlexRay bus communication test and unit redundancy test were made. The result proves the correctness and practicability of the designed redundancy management method and the bus protocol.