Abstract: On the basis of 1980~2010 observed visibility data from 14 stations in Chengdu,spatial and temporal distribution of low visibility based on civil aviation meteorological standard is analysed preliminarily.Results show:Heavy fog (visibility<600m) impacting flight seriously is likely to happen in the south,southwest and east of Chengdu in the morning,and it can last long in some parts of these districts.Moreover,heavy fog can generate in the night in Xinjin and Pujiang station.Yet heavy fog hardly happens in northwest part of Chengdu,but fog (600m≤visibility<1000m) can easily happen in Pixian in the moning,and Dujiangyan from afternoon to the evening,both of which are in the district above.From 1980 to 2010,the linear trend of heavy fog days in most stations is inclined to decrease;however,Xinjin station is in rising trend.The other low visibility ranking days fluctuate annually in most stations.