Abstract: By use of microwave radiometer data and automatic observation data,the change characteristics of the runway visual range (RVR) in the radiation fog at Chengdu Shuangliu Airport from 2019 to early 2020 were analyzed. The results show that: (1) The RVR of each runway in the fog varies greatly,02R is the worst and 20R is the best. (2) The temperature of near-surface layer inverted by the microwave radiometer is deviated,which is lower in the afternoon and higher in the early morning than the actual value. it needs to be revised during analysis. (3) The change characteristics of RVR correspond well to the characteristics of near-surface inversion layer and virtual potential temperature,which can be used to predict the change of RVR more accurately. Especially the time when RVR rises to the critical value of 550m.