Using precipitation data in flood period (from June to August) at 160 meteorological stations in China as predictands and 74 circulation characteristic indexes as predictors, a running prediction in flood period was conducted. The significant linear trend between predictands and circulation characteristic indexes was considered, as well as their correlation instability. Using running correlation, stepwise regression and ensemble analysis method, the multiple regression assembling prediction models of precipitation in flood period of 2009 at 160 stations were founded, and the independent swatch forecastings for the last 10 years were tested. It shows that the scores for ACC, PS and TS of the test all were better than those of operation of NCC in the recent years. The outputs through running correlation, stepwise regression and ensemble analysis method all have potential operational applications.