In order to improve the real-time and reliability of communication for the small unmanned aircraft engine control system, a kind of small unmanned aircraft airborne equipment communication system based on CAN bus is designed. Both responsive and time-sharing send mechanism were used in the system. A multi ID CAN bus communication program and synchronous sequence based on PIC MCU were designed. The engine control system CAN bus communication was designed in detail. Engine run test and flight test were used to validate the system. The experimental results show that the system design is reasonable. It can improve the communication rate and the anti-interference ability of the engine control system, meanwhile, it meet the requirements of the real-time and reliable communication between the engine control system and various airborne devices. It can be widely used in the small unmanned aerial vehicle communication system.