<p>Research on the mechanism of sound perception in the cochlea has always been an important challenge for scientists of humans. Therefore, the frequency response of stereocilia in the cochlear different regions and the changes in tip link tension was researched, which may deepen the understanding of the physiological role of stereocilia in relation to their biomechanical behaviours and the frequency encoding mechanism in the auditory system. In this paper, the stereocilia motion is described as a forced vibration structure, and the effect of the lymphatic fluid in the cochlea on the stereocilia is considered, and a stereocilia motion model is established. The tension distribution of the tip link at different frequencies was solved. The correctness of the model was proved by comparing the response frequencies of the tip links at different positions with the Greenwood frequency. An increase in the elastic modulus of stereocilia leads to a non-linear decrease in the tension of the tip link, while an increase in the elastic modulus of the tip link leads to an increase in the tension of the tip link. Reducing the proportion of low and medium stereocilia to high stereocilia helps to improve low frequency resolution. In addition, the height gradient of stereocilia has a significant impact on their frequency response characteristics, and there are significant differences in the resolution and response range of stereocilia in different rows of outer hair cells. There are significant differences in the frequency resolution capability and response range of stereocilia of outer hair cells in different rows.</p>