Abstract: Based on the research on the pilot of Hongru River Basin,this paper introduces the development and application of flood control planning decision support system in medium and small river basins.Meanwhile an anatomization on the relative analysed results is also provided.The case indicates the significance of the utilization of decision support system in flood control planning issues because of the ability not only to speed the period,but also to advance the accuracy of the flood control planning.Therefore it is feasible to pay more attention on the research in this field.