Focused on the dynamical collapse of large-span spatial structure, this paper uses giant magnetostrictive material to design a kind of new GMM actuator, which could be used in active vibration control of large-span spatial structure. The genetic algorithm has been used to optimize the position of actuators in large-span spatial structure and the structure of fuzzy control system is introduced. A standard fuzzy logic controller is designed. Fuzzy control routine established by the matlab software is used to carry on the active control simulation analysis on the long-span spatial structures. The research shows that the GMM actuator has fine actuating effectiveness, and can improve the computational efficiency of optimization design at the same time. The genetic algorithm also achieves the overall optimization of the structure and the effect to the fuzzy control is obvious.