Based on the Rayleigh scattering theory, the distribution pattern of the sky light polarization is simulated. The distribution pattern of the sky light polarization in the East China Sea is tested by the photographic full-sky polarization pattern testing system. A method for determining the meridian by the polarization azimuthal angle information is proposed. The research results show that, when the solar altitude angle is larger than 85° or less than 25°, the meridian direction can be positioned by means of the polarization azimuthal angle. The meridian direction is consistent with the theoretical simulation result.