Abstract: MICAPS routine use observational data and Doppler radar data,Zhaoyuan entered the flood season opener against torrential rainstorm circulation background,physical field and radar echoes were analyzed.Showed that:The impact of the storm system is a westerly trough,low shear line and subtropical.The southeastern edge of the subtropical high rapids to provide adequate storm water vapor;Water vapor,dynamic and thermodynamic conditions of moisture convergence with the center line of heavy rainfall,The formation of a favorable upward motion,the cold and warm down,there is a strong unstable stratification,to provide a stable energy storm.