Objective To analyze the pathogenesis of the tinnitus by studying the characteristics of auditory brainstem response(ABR) for subjective idiopathic tinnitus in individuals with normal auditory thresholds and analyzing the relationship between the characteristics and the damage of cochlear low SR fibers and the synapses. Methods To analyze the results of pure tone hearing thresholds, distortion product otoacoustic emission and amplitude, latency, wave interval and amplitude ratio of ABR in 20 male patients with subjective idiopathic tinnitus and normal auditory thresholds and 15 normal controls. Results Compared with normal subjects, the amplitudes of I waves in tinnitus and non-tinnitus ears were significantly decreased(t=-2.621，P=0.012 and t=-2.087，P=0.042), but there was no difference between them. Compared with normal subjects and non-tinnitus ears, the amplitude ratio of III/I in tinnitus ears was significantly increased (t=3.512，P=0.001 and t=2.585，P=0.014) and the latency of ABR I wave was shortened(t=-3.715，P=0.001 and t=-2.049，P=0.047). Conclusion The difference of ABR I wave and the amplitude ratio of III/I between the tinnitus with a normal audiograms and healthy control group may be related to the cochlear damage and the central nervous systems play a vital role in the pathogenesis of subjective idiopathic tinnitus with normal auditory thresholds.