An optical voltage sensor for voltage linear measurement using radial polarization grating is designed. The electro-optic phase delay in a crystal is converted into a synchronous rotation of a ring-shaped facula. The ring-shaped facula is changed into a stripe facula by an image converter

and then the applied voltage can be measured by positioning the dark stripe center with an image collecting system. The linear relation between the electro-optic phase delay and the position of the dark stripe center is proved using Jones matrix. The calculation method and the experimental verification of the bismuth germanium oxide(BGO)crystal and lithium niobate(LN)crystal are given. The results show that the measurement mode of the designed optical voltage sensor is irrelevant to the light intensity

and the measurable range of the electro-optic phase delay reaches 172°

while the linear measurement for voltage is realized with a measurement error less than 0. 5%.