As automobile is exposed to continuous external forces such as road noise and engine vibration, it is necessary to evaluate vehicle components’ vibration durability at the initial design stage. Fatigue failure is one of the frequent failure mechanism occurred in mechanical components when cyclic loading is applied to subject. Fatigue analysis can be classified into two types; quasi-static fatigue analysis dynamic fatigue analysis considering structural resonance. As the tested bracket’s first natural frequency existed in the requirement spec for vibration test (10~50 Hz) so dynamic fatigue analysis should be performed. In this study, vibration analysis was carried out in advance of fatigue analysis. Improving design based on the experiments is inefficient and takes a lot of time and money, so finite element model was constructed. From single components to assembly, modal test was performed and verified the finite element (FE) model within 10% error. Also, boundary conditions were determined using beam elements. After FE model construction, vibration analysis was performed using harmonic analysis. The cause of the failure was analyzed based on simulation results.