Radiation fog and rain fog were determined based on meteorological observation data of 12 stations in Qiannan area from 1991 to 2020, which include minimum visibility, daily precipitation, sunshine duration, cloud cover, air temperature, relative humidity, wind speed and so on.Orthogonal function decomposition (EOF), Mann-Kendall mutation test, linear propensity estimation and other methods were used to analyze the temporal and spatial distribution characteristics of radiation fog and rain fog.The results showed that:The spatial and temporal distributions of radiation fog and rain fog in Qiannan area are quite different.Radiation fog occurs most frequently in Pingtang, Luodian and Longli, while the rain fog occurs most frequently Dushan, Duyun and Changshun.Radiation fog decreased obviously or rain fog unusual increase in recent 10 years in Duyun, Longli, Changshun, Weng "an, Pingtang, Fuquan, Libo and Luodian, which has significant sub-regional characteristics.Radiation fog day is 42.2% more than rain fog day. Radiation fog accounts for 87.1% and the rain fog accounts for 13.9% of the fog process. Radiation fog mainly occur from late summer to winter, and rain fog mainly occur from winter to early spring;Radiation fog decreased significantly after 2012, rain fog increased sharply after 2017, all of which showed a significant mutation.Radiation fog at 9 stations showed a decreasing trend ,while rain fog at 8 stations showed an increasing trend.