Sensitivity analysis is an efficient approach to diagnose model structure and identify the dominant parameters controlling model behavior. It is also a key step in modeling practice. The global sensitivity of parameters of the Xinanjing model is analyzed using Extend FAST method in the Liuxihe reservoir catchment. Results show that the sensitivity of four object functions perform is different. The sensitivity can be influenced by many factors

such as the initial condition and flood type. The results are compared with the scatter map generated by the GLUE uncertainty method. Both methods can get comparable sensitivity analysis results. The main effect sensitivity and interaction effect sensitivity calculated by Extend FAST also supply quantitative indices to help understand the uncertainty in hydrological model.