SWAT model was used in Jurong Reservoir basin in this paper and the nitrogen absorbed by plant, organic nitrogen and nitrate nitrogen output were simulated. The result shows that the nitrogen absorbed by plant is relatively large in upland, paddy field and forestland, and the from sequence of organic nitrogen output from big to small is upland, forestland, paddy field, residential area, water region construction site. In upland and paddy field, the NO3-N from surface runoff, interflow and subsurface runoff are much more than those in other land use types. Meanwhile, the annual output law is also analyzed, and the result shows that the nitrogen output mainly appears in ample flow month.