Based on the Shuangliu International Airport automatic detection data and ERA_interim reanalysis data, a comparative analysis was made on the weather background and meteorological elements characteristics of the two fog processes on November 26 and December 04, 2017. The results show that: the two fog processes are typical radiation fogs, the formation process has some similar circulation background, namely, the cloud is less, the breeze (0~2 m/s), high humidity in the lower layer and the lower stable layer (the lower boundary layer height). The absolute moisture content of the near ground on December 04 is greater than that of November 26. This may be the reason that the minimally dominant visibility and minimum RVR in the fog process of December 04 is less than November 26, and the duration of fog processe is greater than that of November 26. The turbulence in the boundary layer is stronger in the process of December 04, this strong perturbation signal may be of great significance to the development of the heavy fog process which affects the operation of the civil aviation of Shuangliu international airport.