Extreme weather events are highly susceptible to serious meteorological disasters, causing serious damage to human life and property and national economic construction and national defense construction. Using the ERA-Interim analysis data of the European Center (ECMWF), the original raw anomaly (RA) and normalized anomaly (NA), which are effective in the analysis and prediction of extreme weather, are analyzed and predicted for the extreme heavy precipitation process of Nantong on July 11, 2016. The study shows that RA and NA are more advantageous to analyze and forecast the heavy precipitation process than the commonly used original field. The original field commonly used in daily business, it is difficult to give the forecast skills which has good indication significance to extreme precipitation, in contrast, the distance between RA and NA can give a more effective forecast of extreme precipitation. This shows that extreme precipitation events are directly related to the anomaly of meteorological elements. The extreme precipitation area is close to the negative distance level center of RA and NA with potential height, and the time and position of the occurrence of the RA and NA positive distance of humidity are also closely related to the time and position of precipitation, and the intensity of precipitation is also related to the distance level strength of RA and NA with humidity and potential height. Comprehensive analysis of RA and NA with different height and position of potential height and humidity ca n give great help in the analysis and prediction of the rainfall area, intensity and occurrence period of potential extreme weather. Using the model forecast data of ECMWF, by analyzing the forecast results of different aging on the precipitation of the process and the height of 850 hPa potential, compared with the forecast of precipitation itself, the model has a more robust forecast of the NA field of 850 hPa potential height, which is more favorable for forecasters to grasp of the extreme precipitation event.