Abstract: To analyze the hydrology response of climate change and runoff in Batang River basin in the source area of Yangtze River, SWAT(Soil and Water Assessment Tool) model was established based on the DEM (Digital Elevation Model), meteorological data, soil type and land use map data. Furthermore, SUFI-2(Sequential Uncertainty Fitting) was employed to calibrate and validate the model. The simulation results showed that the peak values of observed and simulated runoff were roughly similar, and the peak values were in June, July, August and September; the valley values were in January and February. Factor of groundwater delay was the most essential factor affecting the simulation result. The determination coefficient and efficiency coefficient of the simulated and observed runoff both in calibration period and validation period were all greater than 0.8, indicating that the SWAT model is suitable for the Batang River basin, but was largely affected by frozen soil. On the basis of runoff simulation and analysis of affecting factors, better risk analysis and prediction of mountain torrents and debris flow hazards for the Batang River basin will be taken according to the previous work.

Key words: SWAT, runoff simulation, sensitivity analysis, parameter calibration, model validation