Abstract: A simple bogus typhoon treatment is used in the mesoscale model MM4 to successfully simulate Typhoon 8805 before and after landfall and associated "unusually heavy rain".For better simulation of the process,the physical quantities around the eye of the storm are modified to produce initialized field that is very close to reality.It is understood that from the modelled results that the center of rainfall intensity is basically variable with the landing and movement of typhoon, being consistent with or a little ahead of the track.The rainfall reaches the maximum at the point of landfall.It is found to change in agreement with the evolution of updraft in typhoon by getting heavier with stronger upward motion.