Flood simulation by using a distributed hydrological model (DHM) has been implemented to support dam operation. This study aims to investigate the applicability of Satellite Based Precipitation (SBP) combined with local rain gauge network as input for flood forecast at Chao Phraya basin, Thailand. DHM was set-up at contributing area to Bhumipol dam for inflow forecast in order to protect lower region. As input data, SBP was combined with local gauge network targeting effect of monsoon. DHM was run during 2007-2010 to validate the spatial and temporal accuracy of corrected SBP. The approach showed reduction of the large overestimations of SBP. Then, the accuracy of discharge simulation was successfully improved. The results indicate feasibility to estimate inflow of Bhumipol dam using corrected SBP with local gauge network. Moreover, this method can be useful not only for risk assessment of flooding, but also support proper dam operation.