The skylight polarization distribution pattern in Yellow Sea is studied. The distribution properties of polarization pattern of the sunlight and the moonlight above the sea are analyzed, and the effects of clouds are also investigated. The polarization distribution patterns of the sunlight and the moonlight are simulated based on the Rayleigh scattering theory, and then the polarization patterns of the sunlight and the moonlight in Yellow Sea are measured with an image full-sky polarization pattern measurement system. The polarization measured results of the sunlight and the moonlight are compared with the simulated results. The differences and similarities of neutral points and the direction of the meridian in the polarization pattern are analyzed emphatically. The results reveal that the measured directions of the meridian of sunlight and moonlight are mostly in accord with the theoretical results. The measured neutral points of sunlight have the same rules as the theoretical patterns, but the measured neutral points of moonlight are apparently different from the theoretical results. In the civil evening twilight, the skylight polarization pattern is affected by both the moonlight and the sunlight. Owing to the influence of the cloud on the polarization direction angle and the polarization degree, the measurement instrument cannot identify the part of the polarization pattern at present.