Objective To study the biomechanical response to cupulae partition of statoreceptor in the rotational chair test and to provide a quantitive platform for vestibular system assessment. Method Based on the histological slides from the right temporal bones from a healthy volunteer, a threedimensional geometry of membranous labyrinth in the vestibular system was reconstructed. The biomechanical response of the volunteer to sinusoidal rotation chair test (0.8 Hz, ±40°) with the head pitch 30° was numerically simulated by the Lagrangian method. ResultsThe maximum displacement of cupula partition in the right horizontal semicircular canal is 54.2 μm, and 15.9 μm in the posterior semicircular canal as well as 43.7 μm in the anterior semicircular canal. However, the displacement response in the anterior semicircular canal is identical on both ears, and it would counteract the eye movement. Secondly, the normal displacement in the right semicircular canal deflect from the side of canal to the side of utricle, while in the left semicircular canal, it deflect from the side of utricle to the side of canal when the chair rotated to the right, and it is opposite when the chair rotate to the left. Conclusions The biomechanical response to cupulae partition by this numerical simulation is in accordance with Flourens law and Ewald laws.