In order to meet the King Star town of Longjiang County Flood Control and Drought Relief needs, according to the Star hydrological observation accumulated Handa Han River hydrological history of more than five decades, the use of rainfall runoff forecasting methods, statistics through the valley average rainfall, runoff calculations, partition Sulfide, respectively, calculated at rainfall Through the valley of the average rainfall of the impact of pre-calculated times were calculated rainfall runoff depth, to map out plans related to rainfall Application, not only a thorough investigation to be generated by all the rain run-off, but also based on the time of Richard the rain run-off Forecast programming, according to industry standards ministerial national "intelligence hydrological forecasting norms", the program was error testing and assessment of the accuracy, the passing rate for the program of 7 percent for the B Can be used to forecast rainfall