A large number of forests have been shifting into tea plantation with the continuously promoting of agricultural comprehensive development in the hilly area of Tianmuhu Reservoir watershed,so it is urgent to know how tea plantation expansion influence nitrogen loss.Three experimental natural plots were delineated on tea plantation,secondary pine forest and bamboo forest to study nitrogen loss characteristics via runoff from typical land uses in hilly area of Taihuhu upstream watershed,so as to achieve measured parameters of nitrogen loss via runoff for evaluating the water environmental impact of agricultural comprehensive development in hilly area.TN concentrations in surface runoff of tea plantation,secondary pine forest and bamboo forest were 11.25,2.83 and 3.60 mg/L,respectively,mainly in dissolved form.As to subsurface runoff,they were 27.16,3.59 and 1.06 mg/L,respectively, and were mainly made up of DIN for tea plantation and secondary pine forest,especially as nitrate,while DON for bamboo forest.The plot scale surface runoff coefficients of tea plantation,secondary pine forest and bamboo forest were all less than 0.03, so that subsurface runoff was the major source of runoff.Nitrogen loss was raised heavily with the expansion of tea plantation.The loss rate was 103.08 kg N/(ha·a),which was 7.6 and 23.2 times the loss rate of secondary pine forest and bamboo forest,and 86.7%-99.7% of the total load was lost via subsurface runoff.Subsurface runoff should be paid attention to on prevention and control the nitrogen loss via runoff of tea plantations,and besides reducing fertilizer application,the combination of construction of bamboo buffers at the toe of tea plantation slopes and ponds at the outlet of drainage,so as to prevent and control nitrogen loss via runoff by intercepting nitrogen in situ,is also considerable.