The intensive production of greenhouse vegetables in the Taihu Lake region has a high demand for labor and high fertilizer consumption， making a significant contribution to non-point source pollution in this area.Water and fertigation integration technology has excellent potential for labor-saving， improving fertilizer use efficiency， and reducing nitrogen emissions.This technology has been widely used in Northern China for greenhouse vegetable production.However， there is a lack of evaluation of the application’s effectiveness in the Taihu Lake region.In order to clarify the effects of water and fertigation integration technology on fertilizer reduction， efficiency improvement and nitrogen emission reduction on greenhouse tomatoes in the Taihu Lake region， a field experiment was set up with conventional full dose fertilizer(FD) treatment ， non-fertilizer(CK)treatment and a series of treatments with different percentages of nitrogen fertilizer reduction:10%( R10%)，15%( R15%)， 20%( R20%)， 25%( R25%)， 30%( R30%).The effects of water and fertigation integration technology on tomato yield， nitrogen use efficiency， soil ammonia volatilization， and economic efficiency were analyzed in detail.The results showed that under the water and fertigation integration technology reducing the nitrogen fertilizer application of 10% to 20% could effectively increase the tomato yield， and the R15% treatment had the highest yield， nitrogen use efficiency， and economic efficiency.Compared with FD treatment， the R15% treatment increased yield by 6.1%， increased gross profit by 8.4%， reduced ammonia volatilization by 17.7%， and reached a high nitrogen use efficiency of 41.3%.This research could provide scientific guidance for the appropriate application and popularization of water and fertigation integration technology in the Taihu Lake region.