Most important consequences of climate change and land use land cover change are alterations in regional hydrologic cycles, water resource supply demand balance, hydrological extremes and subsequent effects on social economy. In this paper, previous assessments are reviewed and inadequacies in past studies are discussed. For the past time, attention has focused on assessing the impacts of climate change on hydrological resource or the hydrological consequences of land use land cover changes respectively. It is pointed out that system matie dynamic methodology should be adopted to conduct integrated impact assessment of climate change and land use land cover change on water supply demand balance and social economy. For evaluating effects of climate change and land cover change on hydrological process, extremes and soil erosion, it is necessary to develop a physically based distributed model which integrate geographical information systems with hydrologic and water erosion models.