The optimization problems of vibration control of long-span spatial structures are mainly studied.By studying and improving the classic ant colony optimization, this paper proposes the idea and the specific solution to introduce ant colony optimization into solving the optimal layout of dampers in long-span spatial structures, and the effectiveness is verified by the simulation results on typical reticulated shell structures.With the method of ant colony optimization applying on the spatial structures and effective calculation, the optimal layout of dampers which balance the effectiveness of vibration reduction and engineering economy can be obtained accurately.