Abstract: A tailings dam is preparing for the second phase expansion project. Blasting operation of open-air mining is near the tailings dam. For analyzing the influence of blasting vibration to the stability of the tailings dam at the present stage and the second phase expansion stage, this paper gets the fitting vibrationvelocityformula of blasting according to the result of the blasting vibration. Then we calculate and analyze the large velocity ofthe closest to the explosive source whether satisfies the requirements of the blasting safety regulations, and makes use of the Quake/W and Slope/W module of geotechnical software Geo-Studio to simulate calculate about the dynamic stability of the tailings dam at the present stage and the second phase expansion stage. Calculation results show that the large velocity ofthe closest to the