This paper presents an automatic vestibulo-ocular reflex (VOR) function test system which includes the following parts, l. A PC-controlled rotation chair provides the sinusoidal stimuli pattern (0.1 Hz-2.0 Hz) for semicircular canal acceleration input. ll. An electronic circuit amplifies the D.C. Electro-oculography (EOG) signals for recording the eye movement. lll. An efficient algorithm removes the fast phase of nystagmus to reconstruct the slow phase. From the observation of magnitude gain and phase shift between the semicircular canal sinusoidal acceleration input and the eye movement, we can test the vestibular function for clinical purpose. For normal people, the unity gain and 180 degree phase shift. This system will provide the clinician to diagnose the patients with vergio, dizziness and disequilibrium.