In this paper, SWAT model was used to simulate runoff and nitrogen coupling in Huashan hydrological experimental watershed, and effects of the different land use changes on nitrogen transportation was studied. SWAT model was used in the watershed, the hydro- meteorological data from January, 2008 to December, 2013 and the concentration monitoring data of Ammonia nitrogen and nitrate nitrogen from May, 2012 to December, 2013 in the watershed were used to calibrate the model. The model was used to simulate runoff and nitrogen coupling under the present situation and the assumption of scenarios of land use change, the runoff and nitrogen load of the watershed were calculated. The results show that nitrogen loss in the rainy season accounted for a larger proportion of nitrogen loss in a year, the annual rainy season is the key period of controlling nitrogen loss. The potential of nitrogen loss in dry farmland is larger than that in paddy field. The nitrogen load is reduced by the increasing wood - land. Control of nitrogen fertilizer use and strengthen of the ability of soil and water conservation can effectively reduce the nitrogen load in the wa - tershed.