The prediction precision of the precipitation trend over the Haihe River basin in summer (JJA) 2010 and the prediction techniques and major forecast bases are reviewed. The causes of the summer drought in 2010 are analyzed from the aspects of the climatic background, SST，general circulation patterns, etc. It reveals that the Haihe River basin is presently still in a lessrain climate background. The differences in the general circulation patterns were the major causes of the summer drought in 2010, including the preceding SST anomalies, a weaker East Asian Summer Monsoon,and a stronger and more westward subtropical high over the western Pacific. The merits and demerits of forecasting are summarized as well, so to improve the forecasting accuracy of precipitation trends in flood season and provide better climate prediction service.