Frequency plays an important role in biomechanical responses of traumatic brain injury (TBI). Impact loading can amplify brain deformation and aggravate neurological dysfunction due to resonance behavior. This paper summarized the main research methods for frequency response characteristics of brain injury. Specifically, different mathematical methods for the study of frequency response characteristics of brain injury, as well as current understanding on frequency response characteristics were investigated. Then some suggestions for further researches on frequency response characteristics of brain injury were put forward. The results show that finite element method, reduced order model and fluid-solid coupling model are feasible in the study of frequency response characteristics of brain injury. However, there is still a lack of unified understanding about the natural frequency of brain injury, and frequency response characteristics have not been applied in brain injury criteria. Therefore, improving mechanical evaluation of brain injury based on frequency response characteristics is still the research focus.