Abstract: On studying the application of Airda HTG-4 microwave radiometer at Chengdu Shuangliu Airport, it uses cases with fog, icing, rain and thunderstorm to make analysis. That shows the results with the relative humidity (RH) and liquidwater content (LWC) working well for studying convective storms and fogs, which can be used to represent the changes of visibility, or the two-level structure of the air with convective cases. Especially, the RH lower than 6 km and the LWC from 2. 3 km to4. 5 km make effective changes then. The Kindex and SI also work well with convective cases, and have made extra difference when with heavy rain.