Abstract:Based on the daily-per-hour precipitation data from 54 meteorological stations in Jilin Province during 1960-1992 ,sudden cloud-burst process has been analysed and defined. Spatical and temporal distribution and orgraphic influence of unexpectedly hard rain (local suddenly storm rainfall,areal abruptly rain gush,spate) has been analysed. The results show that there were difference between time distribution and orgraphic distribution,which provided climatic scenario foundation for the weather analysis forecast.