In the context of the current issues of watershed non-point source pollution,especially the continuous increasing of nitrogen pollution load,SWAT model was used to divide Qingshan Lake watershed into 46 sub -basins and 189 hydrological response units and further constructed nitrogen non-point source pollution model of the watershed which was calibrated and verified with daily flow measurement during 2005 -2011 and daily nitrogen concentration measurement during July and August,2011. Afterwards,the constructed model was applied to predict temporal and spatial distribution characteristics of the nitrogen load in the future (2030)under the condition of climate changing. Results showed that on the temporal scale,annual average runoff increased by 12.43% in the future,and monthly variation characteristics of nitrogen loss in the future were significant,mainly in the form of NO_3~--N. Nitrogen loss concentrated on the period of July to September was 52.67% of the yearly total loss. In the spatial scale,nitrogen loss was still mainly concentrated in some subwatershed of the central basin and southeastern basin where farmland is the dominant land-use type. The loss of NO_3~--N load in northwest region(mostly covered by natural forests)still kept lower,but a relative large increase of 13.5% would occur.