A hydrological simulation model was developed for the Dashetai watershed in the Inner Mongolia Autonomous Region with LSPC (Loading Simulation Program in C++). Two global sensitivity analysis (GSA) methods, Morris and Sobol, were applied to identify hydrological sensitive parameters and sensitive surface landuse types. The impacts of two GSA methods and model output measures on sensitivity analysis results were also evaluated. The main conclusions are as follows. 1) The model has a good fit for daily and monthly runoff simulation. The R² of the simulated value and the observed value is greater than 0.6, and NSE between them is greater than 0.5, which indicates that LSPC model is suitable for hydrological simulation of inland arid and semiarid areas. 2) The two GSA methods have impacts on the identification of sensitive parameters and the ranking of sensitive indexes; while the impact of the two measurement methods of MAE and MSE is mainly reflected in the identification of sensitive parameters. 3) The sensitive hydrological parameters are lower zone nominal storage (LZSN) and active groundwater evapotranspiration (AGWETP), and the sensitive underlying landuse types are grassland, farmland, forest and water. All have close relationships with precipitation and landuse types in the study area.