Abstract: In the flood control zones of Liaoning Province, there are 22 representative stations of small and mediumsized rivers with catchment area of less than 2000 km² selected. Combined with the period rainfall and site flood peak data of each representative station, the rainfall early warning thresholds of each station in different calculation periods were determined according to the 5-year flood control standard, and regional comprehensive analysis was carried out according to the flood control zones. The rainfall early warning indexes of different flood control zones in Liaoning province were obtained. The research results provide a basis for decision-making of flood management and disaster reduction of small and medium-sized rivers in Liaoning Province.