Abstract: Using the multi-channel infrared brightness temperature data from the Japanese Himawari 8/9 Meteorological Satellite, the nighttime microphysical RGB synthesis scheme was adopted to compare and analyze the satellite images of Tianfu Airport from June 2021 to April 2024. The results show that the RGB synthesis identification method can divide the dense fog weather at Tianfu Airport into three types, which are clear-sky radiation fog, dense advection fog, and rapidly forming post-precipitation fog. Based on the color and texture differences in the nighttime microphysical RGB composite images, the fog and cloud areas can be accurately and quickly identified. For clear-sky radiation fog, the fog area is a thin, pale yellow region, often showing a point and mesh distributions consistent with the hilly terrain. Dense advection fog presents a uniform bright yellow area, covering a large expanse with obvious movement and diffusion trends. Rapidly forming post-precipitation fog shows a dark yellow distribution with obvious multi-layer cloud structure.