Abstract: The residual polarization of optical lens is a key parameter that affects the accuracy of polarization remote sensing detection, polarization military target recognition and precision optical instruments measurement. In order to solve the problem of accurate measurement of polarization degree of large aperture optical lens in visible light band, a measuring device of residual polarization degree of optical lens was studied. The large aperture off-axis parabolic mirror with a surface metal film was used as the collimating light source, by controlling the incident angle of the incident light and reducing the residual polarization degree of the incident light, the consistent Stokes parameters were obtained in the horizontal, vertical, 45° and 135° directions. In order to verify the performance of the device, the residual polarization of the optical lens whose aperture was less than 160 mm in the visible light band were measured by the device. The measuring results show that the residual polarization of the measuring device is less than 0.2%, which can meet the needs of high-precision measurement of residual polarization of the optical lens.