Climate change has caused re-allocation of water resources in the spatial and temporal pattern, leading to more frequent occurrence of extreme hydrological events. Based on the predictions to global and China climate change by the Intergovernmental Panel on Climate Change(IPCC), the authors of this paper analyzed the evolutionary tendency of water resources in the basin above Hongze Lake under the condition of climate change by the method of setting incremental scene and using the climatological data of the years of 1990 to 2011. The results show that the catchment runoff was sensitive to precipitation changes; the evaporation was relatively sensitive to temperature changes. Compared with the baseline period, in the scenario of increasing precipitation and the same temperature, the water resources in the basin will be in the tendency of increasing; in the scenario of the same precipitation and temperature rise, the actual evaporation in the basin will increase, causing the tendency of water resources decreasing; the annual distribution of runoff is greatly influenced by the change of precipitation; runoff annual distribution becomes more concentrated with the increase of precipitation, which may result in the increasing the difference of runoff annual distribution, and increasing the regulating pressure of Hongze Lake.