The structural dynamic property is determined by physical parameters such as mass, damping, stiffness and their distribution. The structural dynamic property alters when these parameters and their distribution change. So the structural dynamic response varies even if the exciting force is same. Maintaining safety and integrity of the structures requires a better understanding of relationship between structural mass distribution, damage and dynamic response. In this study, relationship between structural mass distribution, damage and dynamic response is investigated by experiments. As a demonstration, the experiment of a steel structure with different mass distribution and damage is validated. The mass distribution in the structure is simulated by column welded different dimensional mass block at the top part, and structural damage simulated by sawcutting a crack at the middle part of column. The sweepsine resonance test is applied to study the relationship between structural mass distribution, damage and dynamic response. The structural first resonance dynamic strain response is measured during experiments. The experimental results indicate that the structural first resonance dynamic strain response increase when the asymmetry of mass distribution increases. When the structure is intact, the structural first resonance dynamic strain response at inferior part of column is always bigger than that of response at middle part of column. When the structure is damage, the structural first resonance dynamic strain response at inferior part of column is always less than that of response at middle part of column.