To achieve measurement of voltage direction for optical voltage transformers,theoretical analysis and experimental verification were conducted by the Pockels effect and theory of polarized light,and a measuring method of voltage direction was presented based on the Pockels effect.The relation among different direction voltage,the state of light polarization and light propagating direction were obtained.The results show that,when the value of applied voltage is 100 V,observing toward light,the long and short axis of the transmitted light are located at the spatial angles of 20° and 110°,respectively,and the polarization direction of light passing through a λ/4 wave-plate is located in the second and fourth quadrants of the coordinates,which indicates that the transmitted light is right-lateral elliptically polarized light,the direction of voltage is along the light propagating direction.In addition,the spatial angles are 130° and 40°,and the polarization direction with a λ/4 wave-plate is located in the first and third quadrants,which indicates that the transmitted light is left-lateral elliptically polarized light,the direction of voltage is along the opposite direction of light propagation.The experimental results agree well with the theory,which can guide the design of optical voltage transformers that can measure the magnitude and direction of voltages.