Abstract:According to the circulation situation on 500hPa, the synoptic type of heavy rainstorm occurred in Yancheng city can be divided to two types as typhoon-type and edge-type of subtropic high. Normally, during the heavy rainstorm, the subtropic high should be stronger and trough or shear line often exists at upper level, meantime, the convergence zone formed by cold and warm stream is also obvious. At the same time, it also showed that synoptic systems are deep at vertical direction and the system, respectively, located at low, middle and high level is consistent with each other. On the other hand, the main surface weather systems are composed of the cold front, stationary front, cyclone, and inverse trough of low pressure.