In order to study the applicability of the Liuxihe model in the flood forecast for the small and medium sized watershed，the flood forecasting system based on Liuxihe model in Xiangshui River Basin of Jiangxi province was set up.In the study，according to the classification of different river were constructed based on level 1 channel，1～2 grade，1～3 model of the flow of the river channel；Parameter optimization using 1 a flood；Verified with 50 flood flood simulation accuracy.The results show that the classification has a great influence on accuracy of Liuxihe model simulation，based on level 1～3 channel the flow of river model can well simulate the flood process；The Liuxihe model can effectively optimize the model’s parameters with only one measured flood，thus it takes great advantages in the application of real-time flood forecasting of small and medium sized watersheds in China.Liuxihe model，the simulation effect is good，can be used in meijiang river basin flood forecasting.