Abstract: Using radar image data, satellite data, lightning positioning data and sounding data, the cases of thunderstorm weather happened in the Yangtze River Delta Region during the year 2004 to 2013 were statistically analyzed and the temporal and spatial distribution characteristics of thunderstorm weather in this area were worked out. Then the paper divided these thunderstorm cases into five types: in front of trough, subtropical high edge, behind trough, thermal convection under subtropical high and easterly wave. Also, the paper gave the typical mesoscale analysis maps of the above five types of thunderstorm weather. Last, variation of the K index, Si index, CAPE and Pwv value before and after the occurring of these thunderstorm processes were discussed. It was found that before the occurring of thunderstorm, most cases had strong layer stratification instability, that was high K index value, low Si index value, high CAPE and Pwv value. And the layer stratification instability before the occurring of thunderstorm was much stronger from June to September than from October to May in the Yangtze River Delta Region.