The vibration properties of cantilever H steel beam were investigated based on the basic theory of structural dynamics.Structural damage factor was derived as a function of damage location and damage degree.According to the structural frequency response,the frequency square change ratio method was used in preliminary testing and evaluation of structural damage.Finite element analysis software ANSYS was applied to simulate and analyse a cantilever H steel beam under 11 working conditions.In the similation,the element stiffness reduction was adopted to simulate structural damage.Then model tests for the H steel beam were carried out.The calculation and analysis results are of great significance to the damage detection and recognition of cantilever H steel beam structures.