Abstract:Observational data,mesoscale auto weather station data, satellite image and the MM5 data are used to analyze the characteristics and causes of rainstorm of strong tropical storm Bilis.Blocked by subtropical high and added by southwest monsoon,the storm was compensated by vapor,heat and power.Typhoon maintainted persistently and moved slowly,and brought heavy rain to South China.The strong upward motion,the strong divergence at high level and the terrain in southern China are very important to maintain the circulation and increase precipitation.