Abstract: The slant visibility is an important parameter in space survey application, meteorology, remote sensing, and so on. It is wellknown the horizontal visibility has a definite relation with the atmospheric extinction coefficient, which is considered as the fundamental of meterorology,but for the slant visibility, the case is entirely different. Besides related to the atmospheric extinction coefficient, the slant visibility is evaluated to be influenced by many factors, such as the visual direction, the solar zenith angle, etc. Due to the complicated process of solving the radiative transfer equation, so far, few literatures could be obtained that described the clear numerical relations between the slant visibility and those effective factors. In this paper, based on the radiative transfer t