One of the key issues for ocean color investigation using Ocean Color Imager (OCI) radiance is the correction for atmospheric effect. In particular, the water-leaving radiance is an order of magnitude less than that of observed radiance, so the accuracy of the concentration of phytoplankton pigments retrieval depends on the accuracy of the correction of atmospheric effect. According to the magnitude of atmospheric effect, it is divided into three categories: the zero order, Rayleigh scattering; the first order, Mie scattering; the second order, including the effect of multi-scattering, polarization, sea surface roughness, viewing angle and the temporal and spatial variation of pressure and total ozone concentration. The Rayleigh scattering effect on OCI channels is the focus of this paper. The optical thickness of Rayleigh scattering and the transmittance of the atmosphere were calculated using 5 coastal surface data from the Taiwan area. The results show that the optical thickness of Rayleigh scattering and the transmittance of the atmosphere are significantly changed for various locations and seasons. To ensure that the atmospheric model can be used in operation, a model for providing Rayleigh scattering optical thickness and transmittance has been established using three-year surface data.