Based on a self-anchored suspension bridge with a long span and complex structure, this paper makes a detailed analysis of its stress characteristics before damage and damage characteristics after damage through finite element analysis and bridge load test. Aiming at the main vulnerable components of the main girder, a variety of identification methods based on the existing dynamic damage identification methods are selected for comparative analysis of damage identification, and finally an effective method suitable for bridge girder damage monitoring is determined according to the identification effect of each method. Different damages of main girder, bridge tower and suspender are simulated respectively, and then the static and dynamic damage characteristics of the structure under the same conditions before and after the damage are analyzed with the results of nondestructive analysis of the bridge as reference. The results show that the internal force and deformation caused by the same static and dynamic load and the inherent dynamic characteristics of the structure will change correspondingly when different damages occur to the structure, but the change is small for the moderate damage of 20%. After the suspenders fail completely, the deformation and internal force of the bridge will increase greatly, and the cable force of the adjacent suspenders will increase by 50%.