In this study, dynamic behavior of the basilar membrane and cochlear fluid caused by the vibration of the stapes was analyzed using a three-dimensional finite element model of the human cochlea. Numerical results and the measurement results were compared, and the validity of the model was verified. In addition, an influence of perilymphatic fistula on the vibration of the basilar membrane was analyzed. The leakage of the lymph from a perforation opened near the round window did not have the great influence on the vibration of the basilar membrane. In contrast, the amplitude of the basilar membrane decreased when the lymph flowed out through the perforation near the oval window. This result suggests that oval window perilymphatic fistula causes an increase of hearing threshold from the viewpoint of dynamics.