Abstract: On the basis of 1986~2007 observed fog date from 157 stations in Sichuan province, the spatial and temporal characteristics of fog in Sichuan province is analysed preliminary.Resultsshow that annual mean fog days were concentrated in the east of Sichuan.Fog days in Sichuan province are of obvious seasonal and inter-monthly variation in spring and summer which have less annual mean fog days, and in confined areas during autumn and winter, more annual mean fog days occur.Fog usually began at 20:00-08:00 LST and ended at 08:00-12:00 LST, with duration maximum 0~3 h.Linear trend of fog days during 1986~2007 shows the trend of changes in inter-annual variation:were declinied about 40% of the observation stations significantly, it only a few sites were in rising trend significantly.