The sensitivity experiments (STE) of numerical simulation,in which the radar and/or satellite data were incorporated into the PSU/NCAR mesoscale model to modify the initial moisture field,for two kinds of heavy rainfall processes over the Changjiang Huaihe river basin have been performed and compared with the control experiment (CTE) without using radar and satellite data.The results show that there is a great improvement in the simulation for 24 hour precipitation forecasts through the adjustment of water vapour and ascending motion by incorporating of radar and satellite data into the mesoscale model.The area and amount of rainfall obtained by STE are more in agreement with the obtained fact than those from CTE.The impact of radar and/or satellite data on simulation result is different for different types of rainfall process.