Blasting is a conventional technique for mining, but structures adjacent to open pit mines are often damaged by blasting vibration, therefore, durability and safety of these structures are affected. Damage characteristics of a three-floor frame structure on the top of an open pit mine under repeatedly blasting vibration is studied in this paper. The damage model of structural members is made based on the theory of damage mechanics of continuous medium, and an overall damage model of the structure is also established by the method of frequency. The results showed that the Young’s modulus, frequency of the structure decreased as increasing of the blasting times, the damage factors of structural members are bigger than that of the structure; the strength of the structure decreased greatly under repeatedly blasting vibration, the strength of the structure is low. The durability of structures is affected, but the structure will not collapse. The research is helpful for blasting control in open pit mines and design on structures adjacent to open pit mines.