Objective To study the correlation between the expression of HO1 in cochlear with the changes of auditory brainstem response (ABR), 40Hz AERP and auditory steadystate response examination (ASSR) in diffuse traumatic brain injury model rats. Methods Diffuse traumatic brain injury model of rats were established and randomly divided into five groups, i.e. normal control, one week after trauma, 2, 3, and 4 weeks after trauma respectively. Then ABR, 40Hz AERP and ASSR, light microscope, electron microscope, immunohistochemistry technique were used to evaluate the changes of hearing function and morphology. Results The expression of HO1 in the control group was normal, whereas there were obviously changes of HO1 expression in inner ears of the traumatic groups. The differences of thresholds of ABR, 40Hz AERP and ASSR between the traumatic groups and the normal control group were obvious (P<0.05). The expression of HO1 in traumatic groups were significantly associated with the changes of auditory function (P<0.05). Conclusion To varying degrees, the diffuse traumatic brain injury can influence the expression of HO1 in the inner ear and auditory functions of model rats. The changes of thresholds of ABR, 40Hz AERP and ASSR may be associated with that of HO1 expression in inner ear.