The ear is an important sensory organ of the human body. Cochlea has a pivotal role in the hearing system of human. Nearly 300 million people around the world suffer from sensorineural deafness caused by cochlear lesions. Because the mechanism of cochlear sensing is very complex, it has not been understood completely so far, which has become one of the important problems in medicine today. The basilar membrane in the cochlear canal is the supporting structure of all microstructures, the complex coupling motion between basilar membrane and lymph in cochlear canal is the primary condition for generating the cochlear sound sensing function. Therefore, it is essential to study the dynamic behavior of the basement membranes. By dividing the length of the cochlea into a finite number of elements and giving the radial distribution, a set of governing equations is derived for coupling micromechanics with fluid. Then combining these equations with the matrix combination equation, the complete coupling response of basilar membrane and lymph is obtained. The instantaneous responses of the basilar membrane under different excitations, the time domain responses of the resonance position under different frequency excitations, and the effects of the changes of the mass and stiffness of the basilar membrane on its biomechanical properties and hearing function are analyzed. The results showthat the increase of the mass and stiffness of the basilar membrane leads to the weakening of the maximum response, and the increase of the mass causes the maximum response position to move to the bottom of the basilar membrane; the increase of the basilar membrane stiffness causes the maximum response position to move to the top of the basilar membrane; the changing basilar membrane cross-section can rapidly reduce the characteristic frequencies at the middle and top of the cochlea, thus achieving better filtering and amplification of specific frequency excitation, and enabling the cochlea to have a higher resolution in a specific frequency range of 1000–3000 Hz.This computational mathematics model can provide a numerical analysis platform for implementing the clinical evaluation of lesions in the basilar membrane of the inner ear. Compared with the existing finite element models, this method has faster calculation speed and higher efficiency of parameter analysis.