Abstract: This paper use the daily 08,20 L- band radar sounding data of Shapingba basic meteorological station from 2005 to 2010,and for different types of fog during the day boundary layer inversion characteristics were analyzed. The results showed that the fog mainly occurred in the fall and winter seasons,during foggy days whether 08 or 20 have temperature inversion in multilayer existence,various types of fog,the 08 inversion temperature difference are more than 20,and inversion temperature strength for 20 more than 08,regardless of fog days,the 08 inversion layer thickness are more than 20. In general,the inversion layer elements of dense fog are reflected inversion features more obvious characteristics,inversion temperature difference is big,inversion layer thickness thicker,also easier to form a thick fog,and 08 of the inversion elements were higher than 20,08 inversion characteristics are more obvious in this period,it is easy to form fog.