The typical characteristics of small unmanned helicopter are unstable, strong coupling and difficult controlling. In this paper, we designed and implemented a stability augmentation control system based on SelfAdaptive Fuzzy PID. First, a control principle of small unmanned helicopter was analyzed in theory and a stability augmentation control law was designed, which based on SelfAdaptive Fuzzy PID control methods. Second, the hardware based on DSP and software of the control system were completed and applied. Finally, during lots of experiments, we tested the feasibility and validity of the system. The results showed that the dynamic stability of small unmanned helicopter could be improved through the stability augmentation control system. In addition, the system could run stably and had high reliability.