Abstract: The paper aims to predict the trend of flood disaster in Liaoning in flood season accurately, and better serve agriculture and meet the increasing service requirement. The authors set up the objective forecast method of flood disaster trend of each river basin in Liaoning, to provide valuable reference to the practical climate prediction for serving agriculture. The study was based on the precipitation data from June to August of 53 observational stations in Liaoning during 1961-2011. The results showed that: river basins in Liaoning were all small area watershed, so the authors used arithmetic average method to calculate the precipitation of each river basin; except Hunhe watershed’s precipitation increased slightly, the other river basins’precipitation decreased; all the basins’mutation point occurred in the middle of 1960s; the 500 hPa geopotential height field in January, the Pacific SST field in Nino3-4 in January, the Siberian high pressure system of SLP field in February and the southeast Pacific SST field in February had close relationship with the precipitation of each river basin in Liaoning; all the multiple regression prediction equations for each river basin’s precipitation passed the significance test of 0.01 reliability, indicating these regression equations had significant meanings.