Because of the obvious affection of moisture from fog drops on longwave and middlewave infrared radiation, the channel radiation information in both bands is simulated respectively by using a Community Radiative Transfer Model (CRTM) according to the characteristics of the Atmospheric Infrared Sounder (AIRS). After analyzing the underlying surface radiation and upwelling radiation from the model, it is found that 1) to exclude the distraction from the underlying surface, the underlying surface radiation can be subtracted from the bottom layer radiation in CRTM. At this time, the ground layer radiation presents the same distribution as the sea fog. Therefore, this method can be used to monitor the horizontal distribution of sea fog; 2) the upwelling radiation and its gradient variation with altitude can reflect the intensity variation of sea fog in the vertical direction, which can be used to monitor the vertical structure of sea fog; 3) After analyzing the simulated radiation in longwave and middlewave infrared bands, it is found that the channel radiation in both infrared bands can mirror the 3D spatial characteristics of sea fog.